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25  
26  package javax.swing;
27  
28  import java.awt.*;
29  import java.awt.event.*;
30  
31  import java.util.Vector;
32  import java.util.Locale;
33  import java.util.ArrayList;
34  import java.util.Collections;
35  import java.util.List;
36  
37  import java.beans.PropertyChangeEvent;
38  import java.beans.PropertyChangeListener;
39  import java.beans.Transient;
40  
41  import javax.swing.event.*;
42  import javax.accessibility.*;
43  import javax.swing.plaf.*;
44  import javax.swing.text.Position;
45  
46  import java.io.ObjectOutputStream;
47  import java.io.ObjectInputStream;
48  import java.io.IOException;
49  import java.io.Serializable;
50  
51  import sun.swing.SwingUtilities2;
52  import sun.swing.SwingUtilities2.Section;
53  import static sun.swing.SwingUtilities2.Section.*;
54  
55  
56  /**
57   * A component that displays a list of objects and allows the user to select
58   * one or more items. A separate model, {@code ListModel}, maintains the
59   * contents of the list.
60   * <p>
61   * It's easy to display an array or Vector of objects, using the {@code JList}
62   * constructor that automatically builds a read-only {@code ListModel} instance
63   * for you:
64   * <pre>
65   * {@code
66   * // Create a JList that displays strings from an array
67   *
68   * String[] data = {"one", "two", "three", "four"};
69   * JList<String> myList = new JList<String>(data);
70   *
71   * // Create a JList that displays the superclasses of JList.class, by
72   * // creating it with a Vector populated with this data
73   *
74   * Vector<Class<?>> superClasses = new Vector<Class<?>>();
75   * Class<JList> rootClass = javax.swing.JList.class;
76   * for(Class<?> cls = rootClass; cls != null; cls = cls.getSuperclass()) {
77   *     superClasses.addElement(cls);
78   * }
79   * JList<Class<?>> myList = new JList<Class<?>>(superClasses);
80   *
81   * // The automatically created model is stored in JList's "model"
82   * // property, which you can retrieve
83   *
84   * ListModel<Class<?>> model = myList.getModel();
85   * for(int i = 0; i < model.getSize(); i++) {
86   *     System.out.println(model.getElementAt(i));
87   * }
88   * }
89   * </pre>
90   * <p>
91   * A {@code ListModel} can be supplied directly to a {@code JList} by way of a
92   * constructor or the {@code setModel} method. The contents need not be static -
93   * the number of items, and the values of items can change over time. A correct
94   * {@code ListModel} implementation notifies the set of
95   * {@code javax.swing.event.ListDataListener}s that have been added to it, each
96   * time a change occurs. These changes are characterized by a
97   * {@code javax.swing.event.ListDataEvent}, which identifies the range of list
98   * indices that have been modified, added, or removed. {@code JList}'s
99   * {@code ListUI} is responsible for keeping the visual representation up to
100  * date with changes, by listening to the model.
101  * <p>
102  * Simple, dynamic-content, {@code JList} applications can use the
103  * {@code DefaultListModel} class to maintain list elements. This class
104  * implements the {@code ListModel} interface and also provides a
105  * <code>java.util.Vector</code>-like API. Applications that need a more
106  * custom <code>ListModel</code> implementation may instead wish to subclass
107  * {@code AbstractListModel}, which provides basic support for managing and
108  * notifying listeners. For example, a read-only implementation of
109  * {@code AbstractListModel}:
110  * <pre>
111  * {@code
112  * // This list model has about 2^16 elements.  Enjoy scrolling.
113  *
114  * ListModel<String> bigData = new AbstractListModel<String>() {
115  *     public int getSize() { return Short.MAX_VALUE; }
116  *     public String getElementAt(int index) { return "Index " + index; }
117  * };
118  * }
119  * </pre>
120  * <p>
121  * The selection state of a {@code JList} is managed by another separate
122  * model, an instance of {@code ListSelectionModel}. {@code JList} is
123  * initialized with a selection model on construction, and also contains
124  * methods to query or set this selection model. Additionally, {@code JList}
125  * provides convenient methods for easily managing the selection. These methods,
126  * such as {@code setSelectedIndex} and {@code getSelectedValue}, are cover
127  * methods that take care of the details of interacting with the selection
128  * model. By default, {@code JList}'s selection model is configured to allow any
129  * combination of items to be selected at a time; selection mode
130  * {@code MULTIPLE_INTERVAL_SELECTION}. The selection mode can be changed
131  * on the selection model directly, or via {@code JList}'s cover method.
132  * Responsibility for updating the selection model in response to user gestures
133  * lies with the list's {@code ListUI}.
134  * <p>
135  * A correct {@code ListSelectionModel} implementation notifies the set of
136  * {@code javax.swing.event.ListSelectionListener}s that have been added to it
137  * each time a change to the selection occurs. These changes are characterized
138  * by a {@code javax.swing.event.ListSelectionEvent}, which identifies the range
139  * of the selection change.
140  * <p>
141  * The preferred way to listen for changes in list selection is to add
142  * {@code ListSelectionListener}s directly to the {@code JList}. {@code JList}
143  * then takes care of listening to the the selection model and notifying your
144  * listeners of change.
145  * <p>
146  * Responsibility for listening to selection changes in order to keep the list's
147  * visual representation up to date lies with the list's {@code ListUI}.
148  * <p>
149  * <a name="renderer"></a>
150  * Painting of cells in a {@code JList} is handled by a delegate called a
151  * cell renderer, installed on the list as the {@code cellRenderer} property.
152  * The renderer provides a {@code java.awt.Component} that is used
153  * like a "rubber stamp" to paint the cells. Each time a cell needs to be
154  * painted, the list's {@code ListUI} asks the cell renderer for the component,
155  * moves it into place, and has it paint the contents of the cell by way of its
156  * {@code paint} method. A default cell renderer, which uses a {@code JLabel}
157  * component to render, is installed by the lists's {@code ListUI}. You can
158  * substitute your own renderer using code like this:
159  * <pre>
160  * {@code
161  *  // Display an icon and a string for each object in the list.
162  *
163  * class MyCellRenderer extends JLabel implements ListCellRenderer<Object> {
164  *     final static ImageIcon longIcon = new ImageIcon("long.gif");
165  *     final static ImageIcon shortIcon = new ImageIcon("short.gif");
166  *
167  *     // This is the only method defined by ListCellRenderer.
168  *     // We just reconfigure the JLabel each time we're called.
169  *
170  *     public Component getListCellRendererComponent(
171  *       JList<?> list,           // the list
172  *       Object value,            // value to display
173  *       int index,               // cell index
174  *       boolean isSelected,      // is the cell selected
175  *       boolean cellHasFocus)    // does the cell have focus
176  *     {
177  *         String s = value.toString();
178  *         setText(s);
179  *         setIcon((s.length() > 10) ? longIcon : shortIcon);
180  *         if (isSelected) {
181  *             setBackground(list.getSelectionBackground());
182  *             setForeground(list.getSelectionForeground());
183  *         } else {
184  *             setBackground(list.getBackground());
185  *             setForeground(list.getForeground());
186  *         }
187  *         setEnabled(list.isEnabled());
188  *         setFont(list.getFont());
189  *         setOpaque(true);
190  *         return this;
191  *     }
192  * }
193  *
194  * myList.setCellRenderer(new MyCellRenderer());
195  * }
196  * </pre>
197  * <p>
198  * Another job for the cell renderer is in helping to determine sizing
199  * information for the list. By default, the list's {@code ListUI} determines
200  * the size of cells by asking the cell renderer for its preferred
201  * size for each list item. This can be expensive for large lists of items.
202  * To avoid these calculations, you can set a {@code fixedCellWidth} and
203  * {@code fixedCellHeight} on the list, or have these values calculated
204  * automatically based on a single prototype value:
205  * <a name="prototype_example"></a>
206  * <pre>
207  * {@code
208  * JList<String> bigDataList = new JList<String>(bigData);
209  *
210  * // We don't want the JList implementation to compute the width
211  * // or height of all of the list cells, so we give it a string
212  * // that's as big as we'll need for any cell.  It uses this to
213  * // compute values for the fixedCellWidth and fixedCellHeight
214  * // properties.
215  *
216  * bigDataList.setPrototypeCellValue("Index 1234567890");
217  * }
218  * </pre>
219  * <p>
220  * {@code JList} doesn't implement scrolling directly. To create a list that
221  * scrolls, make it the viewport view of a {@code JScrollPane}. For example:
222  * <pre>
223  * JScrollPane scrollPane = new JScrollPane(myList);
224  *
225  * // Or in two steps:
226  * JScrollPane scrollPane = new JScrollPane();
227  * scrollPane.getViewport().setView(myList);
228  * </pre>
229  * <p>
230  * {@code JList} doesn't provide any special handling of double or triple
231  * (or N) mouse clicks, but it's easy to add a {@code MouseListener} if you
232  * wish to take action on these events. Use the {@code locationToIndex}
233  * method to determine what cell was clicked. For example:
234  * <pre>
235  * MouseListener mouseListener = new MouseAdapter() {
236  *     public void mouseClicked(MouseEvent e) {
237  *         if (e.getClickCount() == 2) {
238  *             int index = list.locationToIndex(e.getPoint());
239  *             System.out.println("Double clicked on Item " + index);
240  *          }
241  *     }
242  * };
243  * list.addMouseListener(mouseListener);
244  * </pre>
245  * <p>
246  * <strong>Warning:</strong> Swing is not thread safe. For more
247  * information see <a
248  * href="package-summary.html#threading">Swing's Threading
249  * Policy</a>.
250  * <p>
251  * <strong>Warning:</strong>
252  * Serialized objects of this class will not be compatible with
253  * future Swing releases. The current serialization support is
254  * appropriate for short term storage or RMI between applications running
255  * the same version of Swing.  As of 1.4, support for long term storage
256  * of all JavaBeans&trade;
257  * has been added to the <code>java.beans</code> package.
258  * Please see {@link java.beans.XMLEncoder}.
259  * <p>
260  * See <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/list.html">How to Use Lists</a>
261  * in <a href="http://docs.oracle.com/javase/tutorial/"><em>The Java Tutorial</em></a>
262  * for further documentation.
263  * <p>
264  * @see ListModel
265  * @see AbstractListModel
266  * @see DefaultListModel
267  * @see ListSelectionModel
268  * @see DefaultListSelectionModel
269  * @see ListCellRenderer
270  * @see DefaultListCellRenderer
271  *
272  * @param <E> the type of the elements of this list
273  *
274  * @beaninfo
275  *   attribute: isContainer false
276  * description: A component which allows for the selection of one or more objects from a list.
277  *
278  * @author Hans Muller
279  */
280 public class JList<E> extends JComponent implements Scrollable, Accessible
281 {
282     /**
283      * @see #getUIClassID
284      * @see #readObject
285      */
286     private static final String uiClassID = "ListUI";
287 
288     /**
289      * Indicates a vertical layout of cells, in a single column;
290      * the default layout.
291      * @see #setLayoutOrientation
292      * @since 1.4
293      */
294     public static final int VERTICAL = 0;
295 
296     /**
297      * Indicates a "newspaper style" layout with cells flowing vertically
298      * then horizontally.
299      * @see #setLayoutOrientation
300      * @since 1.4
301      */
302     public static final int VERTICAL_WRAP = 1;
303 
304     /**
305      * Indicates a "newspaper style" layout with cells flowing horizontally
306      * then vertically.
307      * @see #setLayoutOrientation
308      * @since 1.4
309      */
310     public static final int HORIZONTAL_WRAP = 2;
311 
312     private int fixedCellWidth = -1;
313     private int fixedCellHeight = -1;
314     private int horizontalScrollIncrement = -1;
315     private E prototypeCellValue;
316     private int visibleRowCount = 8;
317     private Color selectionForeground;
318     private Color selectionBackground;
319     private boolean dragEnabled;
320 
321     private ListSelectionModel selectionModel;
322     private ListModel<E> dataModel;
323     private ListCellRenderer<? super E> cellRenderer;
324     private ListSelectionListener selectionListener;
325 
326     /**
327      * How to lay out the cells; defaults to <code>VERTICAL</code>.
328      */
329     private int layoutOrientation;
330 
331     /**
332      * The drop mode for this component.
333      */
334     private DropMode dropMode = DropMode.USE_SELECTION;
335 
336     /**
337      * The drop location.
338      */
339     private transient DropLocation dropLocation;
340 
341     /**
342      * A subclass of <code>TransferHandler.DropLocation</code> representing
343      * a drop location for a <code>JList</code>.
344      *
345      * @see #getDropLocation
346      * @since 1.6
347      */
348     public static final class DropLocation extends TransferHandler.DropLocation {
349         private final int index;
350         private final boolean isInsert;
351 
352         private DropLocation(Point p, int index, boolean isInsert) {
353             super(p);
354             this.index = index;
355             this.isInsert = isInsert;
356         }
357 
358         /**
359          * Returns the index where dropped data should be placed in the
360          * list. Interpretation of the value depends on the drop mode set on
361          * the associated component. If the drop mode is either
362          * <code>DropMode.USE_SELECTION</code> or <code>DropMode.ON</code>,
363          * the return value is an index of a row in the list. If the drop mode is
364          * <code>DropMode.INSERT</code>, the return value refers to the index
365          * where the data should be inserted. If the drop mode is
366          * <code>DropMode.ON_OR_INSERT</code>, the value of
367          * <code>isInsert()</code> indicates whether the index is an index
368          * of a row, or an insert index.
369          * <p>
370          * <code>-1</code> indicates that the drop occurred over empty space,
371          * and no index could be calculated.
372          *
373          * @return the drop index
374          */
375         public int getIndex() {
376             return index;
377         }
378 
379         /**
380          * Returns whether or not this location represents an insert
381          * location.
382          *
383          * @return whether or not this is an insert location
384          */
385         public boolean isInsert() {
386             return isInsert;
387         }
388 
389         /**
390          * Returns a string representation of this drop location.
391          * This method is intended to be used for debugging purposes,
392          * and the content and format of the returned string may vary
393          * between implementations.
394          *
395          * @return a string representation of this drop location
396          */
397         public String toString() {
398             return getClass().getName()
399                    + "[dropPoint=" + getDropPoint() + ","
400                    + "index=" + index + ","
401                    + "insert=" + isInsert + "]";
402         }
403     }
404 
405     /**
406      * Constructs a {@code JList} that displays elements from the specified,
407      * {@code non-null}, model. All {@code JList} constructors delegate to
408      * this one.
409      * <p>
410      * This constructor registers the list with the {@code ToolTipManager},
411      * allowing for tooltips to be provided by the cell renderers.
412      *
413      * @param dataModel the model for the list
414      * @exception IllegalArgumentException if the model is {@code null}
415      */
416     public JList(ListModel<E> dataModel)
417     {
418         if (dataModel == null) {
419             throw new IllegalArgumentException("dataModel must be non null");
420         }
421 
422         // Register with the ToolTipManager so that tooltips from the
423         // renderer show through.
424         ToolTipManager toolTipManager = ToolTipManager.sharedInstance();
425         toolTipManager.registerComponent(this);
426 
427         layoutOrientation = VERTICAL;
428 
429         this.dataModel = dataModel;
430         selectionModel = createSelectionModel();
431         setAutoscrolls(true);
432         setOpaque(true);
433         updateUI();
434     }
435 
436 
437     /**
438      * Constructs a <code>JList</code> that displays the elements in
439      * the specified array. This constructor creates a read-only model
440      * for the given array, and then delegates to the constructor that
441      * takes a {@code ListModel}.
442      * <p>
443      * Attempts to pass a {@code null} value to this method results in
444      * undefined behavior and, most likely, exceptions. The created model
445      * references the given array directly. Attempts to modify the array
446      * after constructing the list results in undefined behavior.
447      *
448      * @param  listData  the array of Objects to be loaded into the data model,
449      *                   {@code non-null}
450      */
451     public JList(final E[] listData)
452     {
453         this (
454             new AbstractListModel<E>() {
455                 public int getSize() { return listData.length; }
456                 public E getElementAt(int i) { return listData[i]; }
457             }
458         );
459     }
460 
461 
462     /**
463      * Constructs a <code>JList</code> that displays the elements in
464      * the specified <code>Vector</code>. This constructor creates a read-only
465      * model for the given {@code Vector}, and then delegates to the constructor
466      * that takes a {@code ListModel}.
467      * <p>
468      * Attempts to pass a {@code null} value to this method results in
469      * undefined behavior and, most likely, exceptions. The created model
470      * references the given {@code Vector} directly. Attempts to modify the
471      * {@code Vector} after constructing the list results in undefined behavior.
472      *
473      * @param  listData  the <code>Vector</code> to be loaded into the
474      *                   data model, {@code non-null}
475      */
476     public JList(final Vector<? extends E> listData) {
477         this (
478             new AbstractListModel<E>() {
479                 public int getSize() { return listData.size(); }
480                 public E getElementAt(int i) { return listData.elementAt(i); }
481             }
482         );
483     }
484 
485 
486     /**
487      * Constructs a <code>JList</code> with an empty, read-only, model.
488      */
489     public JList() {
490         this (
491             new AbstractListModel<E>() {
492               public int getSize() { return 0; }
493               public E getElementAt(int i) { throw new IndexOutOfBoundsException("No Data Model"); }
494             }
495         );
496     }
497 
498 
499     /**
500      * Returns the {@code ListUI}, the look and feel object that
501      * renders this component.
502      *
503      * @return the <code>ListUI</code> object that renders this component
504      */
505     public ListUI getUI() {
506         return (ListUI)ui;
507     }
508 
509 
510     /**
511      * Sets the {@code ListUI}, the look and feel object that
512      * renders this component.
513      *
514      * @param ui  the <code>ListUI</code> object
515      * @see UIDefaults#getUI
516      * @beaninfo
517      *        bound: true
518      *       hidden: true
519      *    attribute: visualUpdate true
520      *  description: The UI object that implements the Component's LookAndFeel.
521      */
522     public void setUI(ListUI ui) {
523         super.setUI(ui);
524     }
525 
526 
527     /**
528      * Resets the {@code ListUI} property by setting it to the value provided
529      * by the current look and feel. If the current cell renderer was installed
530      * by the developer (rather than the look and feel itself), this also causes
531      * the cell renderer and its children to be updated, by calling
532      * {@code SwingUtilities.updateComponentTreeUI} on it.
533      *
534      * @see UIManager#getUI
535      * @see SwingUtilities#updateComponentTreeUI
536      */
537     public void updateUI() {
538         setUI((ListUI)UIManager.getUI(this));
539 
540         ListCellRenderer<? super E> renderer = getCellRenderer();
541         if (renderer instanceof Component) {
542             SwingUtilities.updateComponentTreeUI((Component)renderer);
543         }
544     }
545 
546 
547     /**
548      * Returns {@code "ListUI"}, the <code>UIDefaults</code> key used to look
549      * up the name of the {@code javax.swing.plaf.ListUI} class that defines
550      * the look and feel for this component.
551      *
552      * @return the string "ListUI"
553      * @see JComponent#getUIClassID
554      * @see UIDefaults#getUI
555      */
556     public String getUIClassID() {
557         return uiClassID;
558     }
559 
560 
561     /* -----private-----
562      * This method is called by setPrototypeCellValue and setCellRenderer
563      * to update the fixedCellWidth and fixedCellHeight properties from the
564      * current value of prototypeCellValue (if it's non null).
565      * <p>
566      * This method sets fixedCellWidth and fixedCellHeight but does <b>not</b>
567      * generate PropertyChangeEvents for them.
568      *
569      * @see #setPrototypeCellValue
570      * @see #setCellRenderer
571      */
572     private void updateFixedCellSize()
573     {
574         ListCellRenderer<? super E> cr = getCellRenderer();
575         E value = getPrototypeCellValue();
576 
577         if ((cr != null) && (value != null)) {
578             Component c = cr.getListCellRendererComponent(this, value, 0, false, false);
579 
580             /* The ListUI implementation will add Component c to its private
581              * CellRendererPane however we can't assume that's already
582              * been done here.  So we temporarily set the one "inherited"
583              * property that may affect the renderer components preferred size:
584              * its font.
585              */
586             Font f = c.getFont();
587             c.setFont(getFont());
588 
589             Dimension d = c.getPreferredSize();
590             fixedCellWidth = d.width;
591             fixedCellHeight = d.height;
592 
593             c.setFont(f);
594         }
595     }
596 
597 
598     /**
599      * Returns the "prototypical" cell value -- a value used to calculate a
600      * fixed width and height for cells. This can be {@code null} if there
601      * is no such value.
602      *
603      * @return the value of the {@code prototypeCellValue} property
604      * @see #setPrototypeCellValue
605      */
606     public E getPrototypeCellValue() {
607         return prototypeCellValue;
608     }
609 
610     /**
611      * Sets the {@code prototypeCellValue} property, and then (if the new value
612      * is {@code non-null}), computes the {@code fixedCellWidth} and
613      * {@code fixedCellHeight} properties by requesting the cell renderer
614      * component for the given value (and index 0) from the cell renderer, and
615      * using that component's preferred size.
616      * <p>
617      * This method is useful when the list is too long to allow the
618      * {@code ListUI} to compute the width/height of each cell, and there is a
619      * single cell value that is known to occupy as much space as any of the
620      * others, a so-called prototype.
621      * <p>
622      * While all three of the {@code prototypeCellValue},
623      * {@code fixedCellHeight}, and {@code fixedCellWidth} properties may be
624      * modified by this method, {@code PropertyChangeEvent} notifications are
625      * only sent when the {@code prototypeCellValue} property changes.
626      * <p>
627      * To see an example which sets this property, see the
628      * <a href="#prototype_example">class description</a> above.
629      * <p>
630      * The default value of this property is <code>null</code>.
631      * <p>
632      * This is a JavaBeans bound property.
633      *
634      * @param prototypeCellValue  the value on which to base
635      *                          <code>fixedCellWidth</code> and
636      *                          <code>fixedCellHeight</code>
637      * @see #getPrototypeCellValue
638      * @see #setFixedCellWidth
639      * @see #setFixedCellHeight
640      * @see JComponent#addPropertyChangeListener
641      * @beaninfo
642      *       bound: true
643      *   attribute: visualUpdate true
644      * description: The cell prototype value, used to compute cell width and height.
645      */
646     public void setPrototypeCellValue(E prototypeCellValue) {
647         E oldValue = this.prototypeCellValue;
648         this.prototypeCellValue = prototypeCellValue;
649 
650         /* If the prototypeCellValue has changed and is non-null,
651          * then recompute fixedCellWidth and fixedCellHeight.
652          */
653 
654         if ((prototypeCellValue != null) && !prototypeCellValue.equals(oldValue)) {
655             updateFixedCellSize();
656         }
657 
658         firePropertyChange("prototypeCellValue", oldValue, prototypeCellValue);
659     }
660 
661 
662     /**
663      * Returns the value of the {@code fixedCellWidth} property.
664      *
665      * @return the fixed cell width
666      * @see #setFixedCellWidth
667      */
668     public int getFixedCellWidth() {
669         return fixedCellWidth;
670     }
671 
672     /**
673      * Sets a fixed value to be used for the width of every cell in the list.
674      * If {@code width} is -1, cell widths are computed in the {@code ListUI}
675      * by applying <code>getPreferredSize</code> to the cell renderer component
676      * for each list element.
677      * <p>
678      * The default value of this property is {@code -1}.
679      * <p>
680      * This is a JavaBeans bound property.
681      *
682      * @param width the width to be used for all cells in the list
683      * @see #setPrototypeCellValue
684      * @see #setFixedCellWidth
685      * @see JComponent#addPropertyChangeListener
686      * @beaninfo
687      *       bound: true
688      *   attribute: visualUpdate true
689      * description: Defines a fixed cell width when greater than zero.
690      */
691     public void setFixedCellWidth(int width) {
692         int oldValue = fixedCellWidth;
693         fixedCellWidth = width;
694         firePropertyChange("fixedCellWidth", oldValue, fixedCellWidth);
695     }
696 
697 
698     /**
699      * Returns the value of the {@code fixedCellHeight} property.
700      *
701      * @return the fixed cell height
702      * @see #setFixedCellHeight
703      */
704     public int getFixedCellHeight() {
705         return fixedCellHeight;
706     }
707 
708     /**
709      * Sets a fixed value to be used for the height of every cell in the list.
710      * If {@code height} is -1, cell heights are computed in the {@code ListUI}
711      * by applying <code>getPreferredSize</code> to the cell renderer component
712      * for each list element.
713      * <p>
714      * The default value of this property is {@code -1}.
715      * <p>
716      * This is a JavaBeans bound property.
717      *
718      * @param height the height to be used for for all cells in the list
719      * @see #setPrototypeCellValue
720      * @see #setFixedCellWidth
721      * @see JComponent#addPropertyChangeListener
722      * @beaninfo
723      *       bound: true
724      *   attribute: visualUpdate true
725      * description: Defines a fixed cell height when greater than zero.
726      */
727     public void setFixedCellHeight(int height) {
728         int oldValue = fixedCellHeight;
729         fixedCellHeight = height;
730         firePropertyChange("fixedCellHeight", oldValue, fixedCellHeight);
731     }
732 
733 
734     /**
735      * Returns the object responsible for painting list items.
736      *
737      * @return the value of the {@code cellRenderer} property
738      * @see #setCellRenderer
739      */
740     @Transient
741     public ListCellRenderer<? super E> getCellRenderer() {
742         return cellRenderer;
743     }
744 
745     /**
746      * Sets the delegate that is used to paint each cell in the list.
747      * The job of a cell renderer is discussed in detail in the
748      * <a href="#renderer">class level documentation</a>.
749      * <p>
750      * If the {@code prototypeCellValue} property is {@code non-null},
751      * setting the cell renderer also causes the {@code fixedCellWidth} and
752      * {@code fixedCellHeight} properties to be re-calculated. Only one
753      * <code>PropertyChangeEvent</code> is generated however -
754      * for the <code>cellRenderer</code> property.
755      * <p>
756      * The default value of this property is provided by the {@code ListUI}
757      * delegate, i.e. by the look and feel implementation.
758      * <p>
759      * This is a JavaBeans bound property.
760      *
761      * @param cellRenderer the <code>ListCellRenderer</code>
762      *                          that paints list cells
763      * @see #getCellRenderer
764      * @beaninfo
765      *       bound: true
766      *   attribute: visualUpdate true
767      * description: The component used to draw the cells.
768      */
769     public void setCellRenderer(ListCellRenderer<? super E> cellRenderer) {
770         ListCellRenderer<? super E> oldValue = this.cellRenderer;
771         this.cellRenderer = cellRenderer;
772 
773         /* If the cellRenderer has changed and prototypeCellValue
774          * was set, then recompute fixedCellWidth and fixedCellHeight.
775          */
776         if ((cellRenderer != null) && !cellRenderer.equals(oldValue)) {
777             updateFixedCellSize();
778         }
779 
780         firePropertyChange("cellRenderer", oldValue, cellRenderer);
781     }
782 
783 
784     /**
785      * Returns the color used to draw the foreground of selected items.
786      * {@code DefaultListCellRenderer} uses this color to draw the foreground
787      * of items in the selected state, as do the renderers installed by most
788      * {@code ListUI} implementations.
789      *
790      * @return the color to draw the foreground of selected items
791      * @see #setSelectionForeground
792      * @see DefaultListCellRenderer
793      */
794     public Color getSelectionForeground() {
795         return selectionForeground;
796     }
797 
798 
799     /**
800      * Sets the color used to draw the foreground of selected items, which
801      * cell renderers can use to render text and graphics.
802      * {@code DefaultListCellRenderer} uses this color to draw the foreground
803      * of items in the selected state, as do the renderers installed by most
804      * {@code ListUI} implementations.
805      * <p>
806      * The default value of this property is defined by the look and feel
807      * implementation.
808      * <p>
809      * This is a JavaBeans bound property.
810      *
811      * @param selectionForeground  the {@code Color} to use in the foreground
812      *                             for selected list items
813      * @see #getSelectionForeground
814      * @see #setSelectionBackground
815      * @see #setForeground
816      * @see #setBackground
817      * @see #setFont
818      * @see DefaultListCellRenderer
819      * @beaninfo
820      *       bound: true
821      *   attribute: visualUpdate true
822      * description: The foreground color of selected cells.
823      */
824     public void setSelectionForeground(Color selectionForeground) {
825         Color oldValue = this.selectionForeground;
826         this.selectionForeground = selectionForeground;
827         firePropertyChange("selectionForeground", oldValue, selectionForeground);
828     }
829 
830 
831     /**
832      * Returns the color used to draw the background of selected items.
833      * {@code DefaultListCellRenderer} uses this color to draw the background
834      * of items in the selected state, as do the renderers installed by most
835      * {@code ListUI} implementations.
836      *
837      * @return the color to draw the background of selected items
838      * @see #setSelectionBackground
839      * @see DefaultListCellRenderer
840      */
841     public Color getSelectionBackground() {
842         return selectionBackground;
843     }
844 
845 
846     /**
847      * Sets the color used to draw the background of selected items, which
848      * cell renderers can use fill selected cells.
849      * {@code DefaultListCellRenderer} uses this color to fill the background
850      * of items in the selected state, as do the renderers installed by most
851      * {@code ListUI} implementations.
852      * <p>
853      * The default value of this property is defined by the look
854      * and feel implementation.
855      * <p>
856      * This is a JavaBeans bound property.
857      *
858      * @param selectionBackground  the {@code Color} to use for the
859      *                             background of selected cells
860      * @see #getSelectionBackground
861      * @see #setSelectionForeground
862      * @see #setForeground
863      * @see #setBackground
864      * @see #setFont
865      * @see DefaultListCellRenderer
866      * @beaninfo
867      *       bound: true
868      *   attribute: visualUpdate true
869      * description: The background color of selected cells.
870      */
871     public void setSelectionBackground(Color selectionBackground) {
872         Color oldValue = this.selectionBackground;
873         this.selectionBackground = selectionBackground;
874         firePropertyChange("selectionBackground", oldValue, selectionBackground);
875     }
876 
877 
878     /**
879      * Returns the value of the {@code visibleRowCount} property. See the
880      * documentation for {@link #setVisibleRowCount} for details on how to
881      * interpret this value.
882      *
883      * @return the value of the {@code visibleRowCount} property.
884      * @see #setVisibleRowCount
885      */
886     public int getVisibleRowCount() {
887         return visibleRowCount;
888     }
889 
890     /**
891      * Sets the {@code visibleRowCount} property, which has different meanings
892      * depending on the layout orientation: For a {@code VERTICAL} layout
893      * orientation, this sets the preferred number of rows to display without
894      * requiring scrolling; for other orientations, it affects the wrapping of
895      * cells.
896      * <p>
897      * In {@code VERTICAL} orientation:<br>
898      * Setting this property affects the return value of the
899      * {@link #getPreferredScrollableViewportSize} method, which is used to
900      * calculate the preferred size of an enclosing viewport. See that method's
901      * documentation for more details.
902      * <p>
903      * In {@code HORIZONTAL_WRAP} and {@code VERTICAL_WRAP} orientations:<br>
904      * This affects how cells are wrapped. See the documentation of
905      * {@link #setLayoutOrientation} for more details.
906      * <p>
907      * The default value of this property is {@code 8}.
908      * <p>
909      * Calling this method with a negative value results in the property
910      * being set to {@code 0}.
911      * <p>
912      * This is a JavaBeans bound property.
913      *
914      * @param visibleRowCount  an integer specifying the preferred number of
915      *                         rows to display without requiring scrolling
916      * @see #getVisibleRowCount
917      * @see #getPreferredScrollableViewportSize
918      * @see #setLayoutOrientation
919      * @see JComponent#getVisibleRect
920      * @see JViewport
921      * @beaninfo
922      *       bound: true
923      *   attribute: visualUpdate true
924      * description: The preferred number of rows to display without
925      *              requiring scrolling
926      */
927     public void setVisibleRowCount(int visibleRowCount) {
928         int oldValue = this.visibleRowCount;
929         this.visibleRowCount = Math.max(0, visibleRowCount);
930         firePropertyChange("visibleRowCount", oldValue, visibleRowCount);
931     }
932 
933 
934     /**
935      * Returns the layout orientation property for the list: {@code VERTICAL}
936      * if the layout is a single column of cells, {@code VERTICAL_WRAP} if the
937      * layout is "newspaper style" with the content flowing vertically then
938      * horizontally, or {@code HORIZONTAL_WRAP} if the layout is "newspaper
939      * style" with the content flowing horizontally then vertically.
940      *
941      * @return the value of the {@code layoutOrientation} property
942      * @see #setLayoutOrientation
943      * @since 1.4
944      */
945     public int getLayoutOrientation() {
946         return layoutOrientation;
947     }
948 
949 
950     /**
951      * Defines the way list cells are layed out. Consider a {@code JList}
952      * with five cells. Cells can be layed out in one of the following ways:
953      *
954      * <pre>
955      * VERTICAL:          0
956      *                    1
957      *                    2
958      *                    3
959      *                    4
960      *
961      * HORIZONTAL_WRAP:   0  1  2
962      *                    3  4
963      *
964      * VERTICAL_WRAP:     0  3
965      *                    1  4
966      *                    2
967      * </pre>
968      * <p>
969      * A description of these layouts follows:
970      *
971      * <table border="1"
972      *  summary="Describes layouts VERTICAL, HORIZONTAL_WRAP, and VERTICAL_WRAP">
973      *   <tr><th><p style="text-align:left">Value</p></th><th><p style="text-align:left">Description</p></th></tr>
974      *   <tr><td><code>VERTICAL</code>
975      *       <td>Cells are layed out vertically in a single column.
976      *   <tr><td><code>HORIZONTAL_WRAP</code>
977      *       <td>Cells are layed out horizontally, wrapping to a new row as
978      *           necessary. If the {@code visibleRowCount} property is less than
979      *           or equal to zero, wrapping is determined by the width of the
980      *           list; otherwise wrapping is done in such a way as to ensure
981      *           {@code visibleRowCount} rows in the list.
982      *   <tr><td><code>VERTICAL_WRAP</code>
983      *       <td>Cells are layed out vertically, wrapping to a new column as
984      *           necessary. If the {@code visibleRowCount} property is less than
985      *           or equal to zero, wrapping is determined by the height of the
986      *           list; otherwise wrapping is done at {@code visibleRowCount} rows.
987      *  </table>
988      * <p>
989      * The default value of this property is <code>VERTICAL</code>.
990      *
991      * @param layoutOrientation the new layout orientation, one of:
992      *        {@code VERTICAL}, {@code HORIZONTAL_WRAP} or {@code VERTICAL_WRAP}
993      * @see #getLayoutOrientation
994      * @see #setVisibleRowCount
995      * @see #getScrollableTracksViewportHeight
996      * @see #getScrollableTracksViewportWidth
997      * @throws IllegalArgumentException if {@code layoutOrientation} isn't one of the
998      *         allowable values
999      * @since 1.4
1000      * @beaninfo
1001      *       bound: true
1002      *   attribute: visualUpdate true
1003      * description: Defines the way list cells are layed out.
1004      *        enum: VERTICAL JList.VERTICAL
1005      *              HORIZONTAL_WRAP JList.HORIZONTAL_WRAP
1006      *              VERTICAL_WRAP JList.VERTICAL_WRAP
1007      */
1008     public void setLayoutOrientation(int layoutOrientation) {
1009         int oldValue = this.layoutOrientation;
1010         switch (layoutOrientation) {
1011         case VERTICAL:
1012         case VERTICAL_WRAP:
1013         case HORIZONTAL_WRAP:
1014             this.layoutOrientation = layoutOrientation;
1015             firePropertyChange("layoutOrientation", oldValue, layoutOrientation);
1016             break;
1017         default:
1018             throw new IllegalArgumentException("layoutOrientation must be one of: VERTICAL, HORIZONTAL_WRAP or VERTICAL_WRAP");
1019         }
1020     }
1021 
1022 
1023     /**
1024      * Returns the smallest list index that is currently visible.
1025      * In a left-to-right {@code componentOrientation}, the first visible
1026      * cell is found closest to the list's upper-left corner. In right-to-left
1027      * orientation, it is found closest to the upper-right corner.
1028      * If nothing is visible or the list is empty, {@code -1} is returned.
1029      * Note that the returned cell may only be partially visible.
1030      *
1031      * @return the index of the first visible cell
1032      * @see #getLastVisibleIndex
1033      * @see JComponent#getVisibleRect
1034      */
1035     public int getFirstVisibleIndex() {
1036         Rectangle r = getVisibleRect();
1037         int first;
1038         if (this.getComponentOrientation().isLeftToRight()) {
1039             first = locationToIndex(r.getLocation());
1040         } else {
1041             first = locationToIndex(new Point((r.x + r.width) - 1, r.y));
1042         }
1043         if (first != -1) {
1044             Rectangle bounds = getCellBounds(first, first);
1045             if (bounds != null) {
1046                 SwingUtilities.computeIntersection(r.x, r.y, r.width, r.height, bounds);
1047                 if (bounds.width == 0 || bounds.height == 0) {
1048                     first = -1;
1049                 }
1050             }
1051         }
1052         return first;
1053     }
1054 
1055 
1056     /**
1057      * Returns the largest list index that is currently visible.
1058      * If nothing is visible or the list is empty, {@code -1} is returned.
1059      * Note that the returned cell may only be partially visible.
1060      *
1061      * @return the index of the last visible cell
1062      * @see #getFirstVisibleIndex
1063      * @see JComponent#getVisibleRect
1064      */
1065     public int getLastVisibleIndex() {
1066         boolean leftToRight = this.getComponentOrientation().isLeftToRight();
1067         Rectangle r = getVisibleRect();
1068         Point lastPoint;
1069         if (leftToRight) {
1070             lastPoint = new Point((r.x + r.width) - 1, (r.y + r.height) - 1);
1071         } else {
1072             lastPoint = new Point(r.x, (r.y + r.height) - 1);
1073         }
1074         int location = locationToIndex(lastPoint);
1075 
1076         if (location != -1) {
1077             Rectangle bounds = getCellBounds(location, location);
1078 
1079             if (bounds != null) {
1080                 SwingUtilities.computeIntersection(r.x, r.y, r.width, r.height, bounds);
1081                 if (bounds.width == 0 || bounds.height == 0) {
1082                     // Try the top left(LTR) or top right(RTL) corner, and
1083                     // then go across checking each cell for HORIZONTAL_WRAP.
1084                     // Try the lower left corner, and then go across checking
1085                     // each cell for other list layout orientation.
1086                     boolean isHorizontalWrap =
1087                         (getLayoutOrientation() == HORIZONTAL_WRAP);
1088                     Point visibleLocation = isHorizontalWrap ?
1089                         new Point(lastPoint.x, r.y) :
1090                         new Point(r.x, lastPoint.y);
1091                     int last;
1092                     int visIndex = -1;
1093                     int lIndex = location;
1094                     location = -1;
1095 
1096                     do {
1097                         last = visIndex;
1098                         visIndex = locationToIndex(visibleLocation);
1099 
1100                         if (visIndex != -1) {
1101                             bounds = getCellBounds(visIndex, visIndex);
1102                             if (visIndex != lIndex && bounds != null &&
1103                                 bounds.contains(visibleLocation)) {
1104                                 location = visIndex;
1105                                 if (isHorizontalWrap) {
1106                                     visibleLocation.y = bounds.y + bounds.height;
1107                                     if (visibleLocation.y >= lastPoint.y) {
1108                                         // Past visible region, bail.
1109                                         last = visIndex;
1110                                     }
1111                                 }
1112                                 else {
1113                                     visibleLocation.x = bounds.x + bounds.width;
1114                                     if (visibleLocation.x >= lastPoint.x) {
1115                                         // Past visible region, bail.
1116                                         last = visIndex;
1117                                     }
1118                                 }
1119 
1120                             }
1121                             else {
1122                                 last = visIndex;
1123                             }
1124                         }
1125                     } while (visIndex != -1 && last != visIndex);
1126                 }
1127             }
1128         }
1129         return location;
1130     }
1131 
1132 
1133     /**
1134      * Scrolls the list within an enclosing viewport to make the specified
1135      * cell completely visible. This calls {@code scrollRectToVisible} with
1136      * the bounds of the specified cell. For this method to work, the
1137      * {@code JList} must be within a <code>JViewport</code>.
1138      * <p>
1139      * If the given index is outside the list's range of cells, this method
1140      * results in nothing.
1141      *
1142      * @param index  the index of the cell to make visible
1143      * @see JComponent#scrollRectToVisible
1144      * @see #getVisibleRect
1145      */
1146     public void ensureIndexIsVisible(int index) {
1147         Rectangle cellBounds = getCellBounds(index, index);
1148         if (cellBounds != null) {
1149             scrollRectToVisible(cellBounds);
1150         }
1151     }
1152 
1153     /**
1154      * Turns on or off automatic drag handling. In order to enable automatic
1155      * drag handling, this property should be set to {@code true}, and the
1156      * list's {@code TransferHandler} needs to be {@code non-null}.
1157      * The default value of the {@code dragEnabled} property is {@code false}.
1158      * <p>
1159      * The job of honoring this property, and recognizing a user drag gesture,
1160      * lies with the look and feel implementation, and in particular, the list's
1161      * {@code ListUI}. When automatic drag handling is enabled, most look and
1162      * feels (including those that subclass {@code BasicLookAndFeel}) begin a
1163      * drag and drop operation whenever the user presses the mouse button over
1164      * an item and then moves the mouse a few pixels. Setting this property to
1165      * {@code true} can therefore have a subtle effect on how selections behave.
1166      * <p>
1167      * If a look and feel is used that ignores this property, you can still
1168      * begin a drag and drop operation by calling {@code exportAsDrag} on the
1169      * list's {@code TransferHandler}.
1170      *
1171      * @param b whether or not to enable automatic drag handling
1172      * @exception HeadlessException if
1173      *            <code>b</code> is <code>true</code> and
1174      *            <code>GraphicsEnvironment.isHeadless()</code>
1175      *            returns <code>true</code>
1176      * @see java.awt.GraphicsEnvironment#isHeadless
1177      * @see #getDragEnabled
1178      * @see #setTransferHandler
1179      * @see TransferHandler
1180      * @since 1.4
1181      *
1182      * @beaninfo
1183      *  description: determines whether automatic drag handling is enabled
1184      *        bound: false
1185      */
1186     public void setDragEnabled(boolean b) {
1187         if (b && GraphicsEnvironment.isHeadless()) {
1188             throw new HeadlessException();
1189         }
1190         dragEnabled = b;
1191     }
1192 
1193     /**
1194      * Returns whether or not automatic drag handling is enabled.
1195      *
1196      * @return the value of the {@code dragEnabled} property
1197      * @see #setDragEnabled
1198      * @since 1.4
1199      */
1200     public boolean getDragEnabled() {
1201         return dragEnabled;
1202     }
1203 
1204     /**
1205      * Sets the drop mode for this component. For backward compatibility,
1206      * the default for this property is <code>DropMode.USE_SELECTION</code>.
1207      * Usage of one of the other modes is recommended, however, for an
1208      * improved user experience. <code>DropMode.ON</code>, for instance,
1209      * offers similar behavior of showing items as selected, but does so without
1210      * affecting the actual selection in the list.
1211      * <p>
1212      * <code>JList</code> supports the following drop modes:
1213      * <ul>
1214      *    <li><code>DropMode.USE_SELECTION</code></li>
1215      *    <li><code>DropMode.ON</code></li>
1216      *    <li><code>DropMode.INSERT</code></li>
1217      *    <li><code>DropMode.ON_OR_INSERT</code></li>
1218      * </ul>
1219      * The drop mode is only meaningful if this component has a
1220      * <code>TransferHandler</code> that accepts drops.
1221      *
1222      * @param dropMode the drop mode to use
1223      * @throws IllegalArgumentException if the drop mode is unsupported
1224      *         or <code>null</code>
1225      * @see #getDropMode
1226      * @see #getDropLocation
1227      * @see #setTransferHandler
1228      * @see TransferHandler
1229      * @since 1.6
1230      */
1231     public final void setDropMode(DropMode dropMode) {
1232         if (dropMode != null) {
1233             switch (dropMode) {
1234                 case USE_SELECTION:
1235                 case ON:
1236                 case INSERT:
1237                 case ON_OR_INSERT:
1238                     this.dropMode = dropMode;
1239                     return;
1240             }
1241         }
1242 
1243         throw new IllegalArgumentException(dropMode + ": Unsupported drop mode for list");
1244     }
1245 
1246     /**
1247      * Returns the drop mode for this component.
1248      *
1249      * @return the drop mode for this component
1250      * @see #setDropMode
1251      * @since 1.6
1252      */
1253     public final DropMode getDropMode() {
1254         return dropMode;
1255     }
1256 
1257     /**
1258      * Calculates a drop location in this component, representing where a
1259      * drop at the given point should insert data.
1260      *
1261      * @param p the point to calculate a drop location for
1262      * @return the drop location, or <code>null</code>
1263      */
1264     DropLocation dropLocationForPoint(Point p) {
1265         DropLocation location = null;
1266         Rectangle rect = null;
1267 
1268         int index = locationToIndex(p);
1269         if (index != -1) {
1270             rect = getCellBounds(index, index);
1271         }
1272 
1273         switch(dropMode) {
1274             case USE_SELECTION:
1275             case ON:
1276                 location = new DropLocation(p,
1277                     (rect != null && rect.contains(p)) ? index : -1,
1278                     false);
1279 
1280                 break;
1281             case INSERT:
1282                 if (index == -1) {
1283                     location = new DropLocation(p, getModel().getSize(), true);
1284                     break;
1285                 }
1286 
1287                 if (layoutOrientation == HORIZONTAL_WRAP) {
1288                     boolean ltr = getComponentOrientation().isLeftToRight();
1289 
1290                     if (SwingUtilities2.liesInHorizontal(rect, p, ltr, false) == TRAILING) {
1291                         index++;
1292                     // special case for below all cells
1293                     } else if (index == getModel().getSize() - 1 && p.y >= rect.y + rect.height) {
1294                         index++;
1295                     }
1296                 } else {
1297                     if (SwingUtilities2.liesInVertical(rect, p, false) == TRAILING) {
1298                         index++;
1299                     }
1300                 }
1301 
1302                 location = new DropLocation(p, index, true);
1303 
1304                 break;
1305             case ON_OR_INSERT:
1306                 if (index == -1) {
1307                     location = new DropLocation(p, getModel().getSize(), true);
1308                     break;
1309                 }
1310 
1311                 boolean between = false;
1312 
1313                 if (layoutOrientation == HORIZONTAL_WRAP) {
1314                     boolean ltr = getComponentOrientation().isLeftToRight();
1315 
1316                     Section section = SwingUtilities2.liesInHorizontal(rect, p, ltr, true);
1317                     if (section == TRAILING) {
1318                         index++;
1319                         between = true;
1320                     // special case for below all cells
1321                     } else if (index == getModel().getSize() - 1 && p.y >= rect.y + rect.height) {
1322                         index++;
1323                         between = true;
1324                     } else if (section == LEADING) {
1325                         between = true;
1326                     }
1327                 } else {
1328                     Section section = SwingUtilities2.liesInVertical(rect, p, true);
1329                     if (section == LEADING) {
1330                         between = true;
1331                     } else if (section == TRAILING) {
1332                         index++;
1333                         between = true;
1334                     }
1335                 }
1336 
1337                 location = new DropLocation(p, index, between);
1338 
1339                 break;
1340             default:
1341                 assert false : "Unexpected drop mode";
1342         }
1343 
1344         return location;
1345     }
1346 
1347     /**
1348      * Called to set or clear the drop location during a DnD operation.
1349      * In some cases, the component may need to use it's internal selection
1350      * temporarily to indicate the drop location. To help facilitate this,
1351      * this method returns and accepts as a parameter a state object.
1352      * This state object can be used to store, and later restore, the selection
1353      * state. Whatever this method returns will be passed back to it in
1354      * future calls, as the state parameter. If it wants the DnD system to
1355      * continue storing the same state, it must pass it back every time.
1356      * Here's how this is used:
1357      * <p>
1358      * Let's say that on the first call to this method the component decides
1359      * to save some state (because it is about to use the selection to show
1360      * a drop index). It can return a state object to the caller encapsulating
1361      * any saved selection state. On a second call, let's say the drop location
1362      * is being changed to something else. The component doesn't need to
1363      * restore anything yet, so it simply passes back the same state object
1364      * to have the DnD system continue storing it. Finally, let's say this
1365      * method is messaged with <code>null</code>. This means DnD
1366      * is finished with this component for now, meaning it should restore
1367      * state. At this point, it can use the state parameter to restore
1368      * said state, and of course return <code>null</code> since there's
1369      * no longer anything to store.
1370      *
1371      * @param location the drop location (as calculated by
1372      *        <code>dropLocationForPoint</code>) or <code>null</code>
1373      *        if there's no longer a valid drop location
1374      * @param state the state object saved earlier for this component,
1375      *        or <code>null</code>
1376      * @param forDrop whether or not the method is being called because an
1377      *        actual drop occurred
1378      * @return any saved state for this component, or <code>null</code> if none
1379      */
1380     Object setDropLocation(TransferHandler.DropLocation location,
1381                            Object state,
1382                            boolean forDrop) {
1383 
1384         Object retVal = null;
1385         DropLocation listLocation = (DropLocation)location;
1386 
1387         if (dropMode == DropMode.USE_SELECTION) {
1388             if (listLocation == null) {
1389                 if (!forDrop && state != null) {
1390                     setSelectedIndices(((int[][])state)[0]);
1391 
1392                     int anchor = ((int[][])state)[1][0];
1393                     int lead = ((int[][])state)[1][1];
1394 
1395                     SwingUtilities2.setLeadAnchorWithoutSelection(
1396                             getSelectionModel(), lead, anchor);
1397                 }
1398             } else {
1399                 if (dropLocation == null) {
1400                     int[] inds = getSelectedIndices();
1401                     retVal = new int[][] {inds, {getAnchorSelectionIndex(),
1402                                                  getLeadSelectionIndex()}};
1403                 } else {
1404                     retVal = state;
1405                 }
1406 
1407                 int index = listLocation.getIndex();
1408                 if (index == -1) {
1409                     clearSelection();
1410                     getSelectionModel().setAnchorSelectionIndex(-1);
1411                     getSelectionModel().setLeadSelectionIndex(-1);
1412                 } else {
1413                     setSelectionInterval(index, index);
1414                 }
1415             }
1416         }
1417 
1418         DropLocation old = dropLocation;
1419         dropLocation = listLocation;
1420         firePropertyChange("dropLocation", old, dropLocation);
1421 
1422         return retVal;
1423     }
1424 
1425     /**
1426      * Returns the location that this component should visually indicate
1427      * as the drop location during a DnD operation over the component,
1428      * or {@code null} if no location is to currently be shown.
1429      * <p>
1430      * This method is not meant for querying the drop location
1431      * from a {@code TransferHandler}, as the drop location is only
1432      * set after the {@code TransferHandler}'s <code>canImport</code>
1433      * has returned and has allowed for the location to be shown.
1434      * <p>
1435      * When this property changes, a property change event with
1436      * name "dropLocation" is fired by the component.
1437      * <p>
1438      * By default, responsibility for listening for changes to this property
1439      * and indicating the drop location visually lies with the list's
1440      * {@code ListUI}, which may paint it directly and/or install a cell
1441      * renderer to do so. Developers wishing to implement custom drop location
1442      * painting and/or replace the default cell renderer, may need to honor
1443      * this property.
1444      *
1445      * @return the drop location
1446      * @see #setDropMode
1447      * @see TransferHandler#canImport(TransferHandler.TransferSupport)
1448      * @since 1.6
1449      */
1450     public final DropLocation getDropLocation() {
1451         return dropLocation;
1452     }
1453 
1454     /**
1455      * Returns the next list element whose {@code toString} value
1456      * starts with the given prefix.
1457      *
1458      * @param prefix the string to test for a match
1459      * @param startIndex the index for starting the search
1460      * @param bias the search direction, either
1461      * Position.Bias.Forward or Position.Bias.Backward.
1462      * @return the index of the next list element that
1463      * starts with the prefix; otherwise {@code -1}
1464      * @exception IllegalArgumentException if prefix is {@code null}
1465      * or startIndex is out of bounds
1466      * @since 1.4
1467      */
1468     public int getNextMatch(String prefix, int startIndex, Position.Bias bias) {
1469         ListModel<E> model = getModel();
1470         int max = model.getSize();
1471         if (prefix == null) {
1472             throw new IllegalArgumentException();
1473         }
1474         if (startIndex < 0 || startIndex >= max) {
1475             throw new IllegalArgumentException();
1476         }
1477         prefix = prefix.toUpperCase();
1478 
1479         // start search from the next element after the selected element
1480         int increment = (bias == Position.Bias.Forward) ? 1 : -1;
1481         int index = startIndex;
1482         do {
1483             E element = model.getElementAt(index);
1484 
1485             if (element != null) {
1486                 String string;
1487 
1488                 if (element instanceof String) {
1489                     string = ((String)element).toUpperCase();
1490                 }
1491                 else {
1492                     string = element.toString();
1493                     if (string != null) {
1494                         string = string.toUpperCase();
1495                     }
1496                 }
1497 
1498                 if (string != null && string.startsWith(prefix)) {
1499                     return index;
1500                 }
1501             }
1502             index = (index + increment + max) % max;
1503         } while (index != startIndex);
1504         return -1;
1505     }
1506 
1507     /**
1508      * Returns the tooltip text to be used for the given event. This overrides
1509      * {@code JComponent}'s {@code getToolTipText} to first check the cell
1510      * renderer component for the cell over which the event occurred, returning
1511      * its tooltip text, if any. This implementation allows you to specify
1512      * tooltip text on the cell level, by using {@code setToolTipText} on your
1513      * cell renderer component.
1514      * <p>
1515      * <strong>Note:</strong> For <code>JList</code> to properly display the
1516      * tooltips of its renderers in this manner, <code>JList</code> must be a
1517      * registered component with the <code>ToolTipManager</code>. This registration
1518      * is done automatically in the constructor. However, if at a later point
1519      * <code>JList</code> is unregistered, by way of a call to
1520      * {@code setToolTipText(null)}, tips from the renderers will no longer display.
1521      *
1522      * @param event the {@code MouseEvent} to fetch the tooltip text for
1523      * @see JComponent#setToolTipText
1524      * @see JComponent#getToolTipText
1525      */
1526     public String getToolTipText(MouseEvent event) {
1527         if(event != null) {
1528             Point p = event.getPoint();
1529             int index = locationToIndex(p);
1530             ListCellRenderer<? super E> r = getCellRenderer();
1531             Rectangle cellBounds;
1532 
1533             if (index != -1 && r != null && (cellBounds =
1534                                getCellBounds(index, index)) != null &&
1535                                cellBounds.contains(p.x, p.y)) {
1536                 ListSelectionModel lsm = getSelectionModel();
1537                 Component rComponent = r.getListCellRendererComponent(
1538                            this, getModel().getElementAt(index), index,
1539                            lsm.isSelectedIndex(index),
1540                            (hasFocus() && (lsm.getLeadSelectionIndex() ==
1541                                            index)));
1542 
1543                 if(rComponent instanceof JComponent) {
1544                     MouseEvent      newEvent;
1545 
1546                     p.translate(-cellBounds.x, -cellBounds.y);
1547                     newEvent = new MouseEvent(rComponent, event.getID(),
1548                                               event.getWhen(),
1549                                               event.getModifiers(),
1550                                               p.x, p.y,
1551                                               event.getXOnScreen(),
1552                                               event.getYOnScreen(),
1553                                               event.getClickCount(),
1554                                               event.isPopupTrigger(),
1555                                               MouseEvent.NOBUTTON);
1556 
1557                     String tip = ((JComponent)rComponent).getToolTipText(
1558                                               newEvent);
1559 
1560                     if (tip != null) {
1561                         return tip;
1562                     }
1563                 }
1564             }
1565         }
1566         return super.getToolTipText();
1567     }
1568 
1569     /**
1570      * --- ListUI Delegations ---
1571      */
1572 
1573 
1574     /**
1575      * Returns the cell index closest to the given location in the list's
1576      * coordinate system. To determine if the cell actually contains the
1577      * specified location, compare the point against the cell's bounds,
1578      * as provided by {@code getCellBounds}. This method returns {@code -1}
1579      * if the model is empty
1580      * <p>
1581      * This is a cover method that delegates to the method of the same name
1582      * in the list's {@code ListUI}. It returns {@code -1} if the list has
1583      * no {@code ListUI}.
1584      *
1585      * @param location the coordinates of the point
1586      * @return the cell index closest to the given location, or {@code -1}
1587      */
1588     public int locationToIndex(Point location) {
1589         ListUI ui = getUI();
1590         return (ui != null) ? ui.locationToIndex(this, location) : -1;
1591     }
1592 
1593 
1594     /**
1595      * Returns the origin of the specified item in the list's coordinate
1596      * system. This method returns {@code null} if the index isn't valid.
1597      * <p>
1598      * This is a cover method that delegates to the method of the same name
1599      * in the list's {@code ListUI}. It returns {@code null} if the list has
1600      * no {@code ListUI}.
1601      *
1602      * @param index the cell index
1603      * @return the origin of the cell, or {@code null}
1604      */
1605     public Point indexToLocation(int index) {
1606         ListUI ui = getUI();
1607         return (ui != null) ? ui.indexToLocation(this, index) : null;
1608     }
1609 
1610 
1611     /**
1612      * Returns the bounding rectangle, in the list's coordinate system,
1613      * for the range of cells specified by the two indices.
1614      * These indices can be supplied in any order.
1615      * <p>
1616      * If the smaller index is outside the list's range of cells, this method
1617      * returns {@code null}. If the smaller index is valid, but the larger
1618      * index is outside the list's range, the bounds of just the first index
1619      * is returned. Otherwise, the bounds of the valid range is returned.
1620      * <p>
1621      * This is a cover method that delegates to the method of the same name
1622      * in the list's {@code ListUI}. It returns {@code null} if the list has
1623      * no {@code ListUI}.
1624      *
1625      * @param index0 the first index in the range
1626      * @param index1 the second index in the range
1627      * @return the bounding rectangle for the range of cells, or {@code null}
1628      */
1629     public Rectangle getCellBounds(int index0, int index1) {
1630         ListUI ui = getUI();
1631         return (ui != null) ? ui.getCellBounds(this, index0, index1) : null;
1632     }
1633 
1634 
1635     /**
1636      * --- ListModel Support ---
1637      */
1638 
1639 
1640     /**
1641      * Returns the data model that holds the list of items displayed
1642      * by the <code>JList</code> component.
1643      *
1644      * @return the <code>ListModel</code> that provides the displayed
1645      *                          list of items
1646      * @see #setModel
1647      */
1648     public ListModel<E> getModel() {
1649         return dataModel;
1650     }
1651 
1652     /**
1653      * Sets the model that represents the contents or "value" of the
1654      * list, notifies property change listeners, and then clears the
1655      * list's selection.
1656      * <p>
1657      * This is a JavaBeans bound property.
1658      *
1659      * @param model  the <code>ListModel</code> that provides the
1660      *                                          list of items for display
1661      * @exception IllegalArgumentException  if <code>model</code> is
1662      *                                          <code>null</code>
1663      * @see #getModel
1664      * @see #clearSelection
1665      * @beaninfo
1666      *       bound: true
1667      *   attribute: visualUpdate true
1668      * description: The object that contains the data to be drawn by this JList.
1669      */
1670     public void setModel(ListModel<E> model) {
1671         if (model == null) {
1672             throw new IllegalArgumentException("model must be non null");
1673         }
1674         ListModel<E> oldValue = dataModel;
1675         dataModel = model;
1676         firePropertyChange("model", oldValue, dataModel);
1677         clearSelection();
1678     }
1679 
1680 
1681     /**
1682      * Constructs a read-only <code>ListModel</code> from an array of items,
1683      * and calls {@code setModel} with this model.
1684      * <p>
1685      * Attempts to pass a {@code null} value to this method results in
1686      * undefined behavior and, most likely, exceptions. The created model
1687      * references the given array directly. Attempts to modify the array
1688      * after invoking this method results in undefined behavior.
1689      *
1690      * @param listData an array of {@code E} containing the items to
1691      *        display in the list
1692      * @see #setModel
1693      */
1694     public void setListData(final E[] listData) {
1695         setModel (
1696             new AbstractListModel<E>() {
1697                 public int getSize() { return listData.length; }
1698                 public E getElementAt(int i) { return listData[i]; }
1699             }
1700         );
1701     }
1702 
1703 
1704     /**
1705      * Constructs a read-only <code>ListModel</code> from a <code>Vector</code>
1706      * and calls {@code setModel} with this model.
1707      * <p>
1708      * Attempts to pass a {@code null} value to this method results in
1709      * undefined behavior and, most likely, exceptions. The created model
1710      * references the given {@code Vector} directly. Attempts to modify the
1711      * {@code Vector} after invoking this method results in undefined behavior.
1712      *
1713      * @param listData a <code>Vector</code> containing the items to
1714      *                                          display in the list
1715      * @see #setModel
1716      */
1717     public void setListData(final Vector<? extends E> listData) {
1718         setModel (
1719             new AbstractListModel<E>() {
1720                 public int getSize() { return listData.size(); }
1721                 public E getElementAt(int i) { return listData.elementAt(i); }
1722             }
1723         );
1724     }
1725 
1726 
1727     /**
1728      * --- ListSelectionModel delegations and extensions ---
1729      */
1730 
1731 
1732     /**
1733      * Returns an instance of {@code DefaultListSelectionModel}; called
1734      * during construction to initialize the list's selection model
1735      * property.
1736      *
1737      * @return a {@code DefaultListSelecitonModel}, used to initialize
1738      *         the list's selection model property during construction
1739      * @see #setSelectionModel
1740      * @see DefaultListSelectionModel
1741      */
1742     protected ListSelectionModel createSelectionModel() {
1743         return new DefaultListSelectionModel();
1744     }
1745 
1746 
1747     /**
1748      * Returns the current selection model. The selection model maintains the
1749      * selection state of the list. See the class level documentation for more
1750      * details.
1751      *
1752      * @return the <code>ListSelectionModel</code> that maintains the
1753      *         list's selections
1754      *
1755      * @see #setSelectionModel
1756      * @see ListSelectionModel
1757      */
1758     public ListSelectionModel getSelectionModel() {
1759         return selectionModel;
1760     }
1761 
1762 
1763     /**
1764      * Notifies {@code ListSelectionListener}s added directly to the list
1765      * of selection changes made to the selection model. {@code JList}
1766      * listens for changes made to the selection in the selection model,
1767      * and forwards notification to listeners added to the list directly,
1768      * by calling this method.
1769      * <p>
1770      * This method constructs a {@code ListSelectionEvent} with this list
1771      * as the source, and the specified arguments, and sends it to the
1772      * registered {@code ListSelectionListeners}.
1773      *
1774      * @param firstIndex the first index in the range, {@code <= lastIndex}
1775      * @param lastIndex the last index in the range, {@code >= firstIndex}
1776      * @param isAdjusting whether or not this is one in a series of
1777      *        multiple events, where changes are still being made
1778      *
1779      * @see #addListSelectionListener
1780      * @see #removeListSelectionListener
1781      * @see javax.swing.event.ListSelectionEvent
1782      * @see EventListenerList
1783      */
1784     protected void fireSelectionValueChanged(int firstIndex, int lastIndex,
1785                                              boolean isAdjusting)
1786     {
1787         Object[] listeners = listenerList.getListenerList();
1788         ListSelectionEvent e = null;
1789 
1790         for (int i = listeners.length - 2; i >= 0; i -= 2) {
1791             if (listeners[i] == ListSelectionListener.class) {
1792                 if (e == null) {
1793                     e = new ListSelectionEvent(this, firstIndex, lastIndex,
1794                                                isAdjusting);
1795                 }
1796                 ((ListSelectionListener)listeners[i+1]).valueChanged(e);
1797             }
1798         }
1799     }
1800 
1801 
1802     /* A ListSelectionListener that forwards ListSelectionEvents from
1803      * the selectionModel to the JList ListSelectionListeners.  The
1804      * forwarded events only differ from the originals in that their
1805      * source is the JList instead of the selectionModel itself.
1806      */
1807     private class ListSelectionHandler implements ListSelectionListener, Serializable
1808     {
1809         public void valueChanged(ListSelectionEvent e) {
1810             fireSelectionValueChanged(e.getFirstIndex(),
1811                                       e.getLastIndex(),
1812                                       e.getValueIsAdjusting());
1813         }
1814     }
1815 
1816 
1817     /**
1818      * Adds a listener to the list, to be notified each time a change to the
1819      * selection occurs; the preferred way of listening for selection state
1820      * changes. {@code JList} takes care of listening for selection state
1821      * changes in the selection model, and notifies the given listener of
1822      * each change. {@code ListSelectionEvent}s sent to the listener have a
1823      * {@code source} property set to this list.
1824      *
1825      * @param listener the {@code ListSelectionListener} to add
1826      * @see #getSelectionModel
1827      * @see #getListSelectionListeners
1828      */
1829     public void addListSelectionListener(ListSelectionListener listener)
1830     {
1831         if (selectionListener == null) {
1832             selectionListener = new ListSelectionHandler();
1833             getSelectionModel().addListSelectionListener(selectionListener);
1834         }
1835 
1836         listenerList.add(ListSelectionListener.class, listener);
1837     }
1838 
1839 
1840     /**
1841      * Removes a selection listener from the list.
1842      *
1843      * @param listener the {@code ListSelectionListener} to remove
1844      * @see #addListSelectionListener
1845      * @see #getSelectionModel
1846      */
1847     public void removeListSelectionListener(ListSelectionListener listener) {
1848         listenerList.remove(ListSelectionListener.class, listener);
1849     }
1850 
1851 
1852     /**
1853      * Returns an array of all the {@code ListSelectionListener}s added
1854      * to this {@code JList} by way of {@code addListSelectionListener}.
1855      *
1856      * @return all of the {@code ListSelectionListener}s on this list, or
1857      *         an empty array if no listeners have been added
1858      * @see #addListSelectionListener
1859      * @since 1.4
1860      */
1861     public ListSelectionListener[] getListSelectionListeners() {
1862         return listenerList.getListeners(ListSelectionListener.class);
1863     }
1864 
1865 
1866     /**
1867      * Sets the <code>selectionModel</code> for the list to a
1868      * non-<code>null</code> <code>ListSelectionModel</code>
1869      * implementation. The selection model handles the task of making single
1870      * selections, selections of contiguous ranges, and non-contiguous
1871      * selections.
1872      * <p>
1873      * This is a JavaBeans bound property.
1874      *
1875      * @param selectionModel  the <code>ListSelectionModel</code> that
1876      *                          implements the selections
1877      * @exception IllegalArgumentException   if <code>selectionModel</code>
1878      *                                          is <code>null</code>
1879      * @see #getSelectionModel
1880      * @beaninfo
1881      *       bound: true
1882      * description: The selection model, recording which cells are selected.
1883      */
1884     public void setSelectionModel(ListSelectionModel selectionModel) {
1885         if (selectionModel == null) {
1886             throw new IllegalArgumentException("selectionModel must be non null");
1887         }
1888 
1889         /* Remove the forwarding ListSelectionListener from the old
1890          * selectionModel, and add it to the new one, if necessary.
1891          */
1892         if (selectionListener != null) {
1893             this.selectionModel.removeListSelectionListener(selectionListener);
1894             selectionModel.addListSelectionListener(selectionListener);
1895         }
1896 
1897         ListSelectionModel oldValue = this.selectionModel;
1898         this.selectionModel = selectionModel;
1899         firePropertyChange("selectionModel", oldValue, selectionModel);
1900     }
1901 
1902 
1903     /**
1904      * Sets the selection mode for the list. This is a cover method that sets
1905      * the selection mode directly on the selection model.
1906      * <p>
1907      * The following list describes the accepted selection modes:
1908      * <ul>
1909      * <li>{@code ListSelectionModel.SINGLE_SELECTION} -
1910      *   Only one list index can be selected at a time. In this mode,
1911      *   {@code setSelectionInterval} and {@code addSelectionInterval} are
1912      *   equivalent, both replacing the current selection with the index
1913      *   represented by the second argument (the "lead").
1914      * <li>{@code ListSelectionModel.SINGLE_INTERVAL_SELECTION} -
1915      *   Only one contiguous interval can be selected at a time.
1916      *   In this mode, {@code addSelectionInterval} behaves like
1917      *   {@code setSelectionInterval} (replacing the current selection},
1918      *   unless the given interval is immediately adjacent to or overlaps
1919      *   the existing selection, and can be used to grow the selection.
1920      * <li>{@code ListSelectionModel.MULTIPLE_INTERVAL_SELECTION} -
1921      *   In this mode, there's no restriction on what can be selected.
1922      *   This mode is the default.
1923      * </ul>
1924      *
1925      * @param selectionMode the selection mode
1926      * @see #getSelectionMode
1927      * @throws IllegalArgumentException if the selection mode isn't
1928      *         one of those allowed
1929      * @beaninfo
1930      * description: The selection mode.
1931      *        enum: SINGLE_SELECTION            ListSelectionModel.SINGLE_SELECTION
1932      *              SINGLE_INTERVAL_SELECTION   ListSelectionModel.SINGLE_INTERVAL_SELECTION
1933      *              MULTIPLE_INTERVAL_SELECTION ListSelectionModel.MULTIPLE_INTERVAL_SELECTION
1934      */
1935     public void setSelectionMode(int selectionMode) {
1936         getSelectionModel().setSelectionMode(selectionMode);
1937     }
1938 
1939     /**
1940      * Returns the current selection mode for the list. This is a cover
1941      * method that delegates to the method of the same name on the
1942      * list's selection model.
1943      *
1944      * @return the current selection mode
1945      * @see #setSelectionMode
1946      */
1947     public int getSelectionMode() {
1948         return getSelectionModel().getSelectionMode();
1949     }
1950 
1951 
1952     /**
1953      * Returns the anchor selection index. This is a cover method that
1954      * delegates to the method of the same name on the list's selection model.
1955      *
1956      * @return the anchor selection index
1957      * @see ListSelectionModel#getAnchorSelectionIndex
1958      */
1959     public int getAnchorSelectionIndex() {
1960         return getSelectionModel().getAnchorSelectionIndex();
1961     }
1962 
1963 
1964     /**
1965      * Returns the lead selection index. This is a cover method that
1966      * delegates to the method of the same name on the list's selection model.
1967      *
1968      * @return the lead selection index
1969      * @see ListSelectionModel#getLeadSelectionIndex
1970      * @beaninfo
1971      * description: The lead selection index.
1972      */
1973     public int getLeadSelectionIndex() {
1974         return getSelectionModel().getLeadSelectionIndex();
1975     }
1976 
1977 
1978     /**
1979      * Returns the smallest selected cell index, or {@code -1} if the selection
1980      * is empty. This is a cover method that delegates to the method of the same
1981      * name on the list's selection model.
1982      *
1983      * @return the smallest selected cell index, or {@code -1}
1984      * @see ListSelectionModel#getMinSelectionIndex
1985      */
1986     public int getMinSelectionIndex() {
1987         return getSelectionModel().getMinSelectionIndex();
1988     }
1989 
1990 
1991     /**
1992      * Returns the largest selected cell index, or {@code -1} if the selection
1993      * is empty. This is a cover method that delegates to the method of the same
1994      * name on the list's selection model.
1995      *
1996      * @return the largest selected cell index
1997      * @see ListSelectionModel#getMaxSelectionIndex
1998      */
1999     public int getMaxSelectionIndex() {
2000         return getSelectionModel().getMaxSelectionIndex();
2001     }
2002 
2003 
2004     /**
2005      * Returns {@code true} if the specified index is selected,
2006      * else {@code false}. This is a cover method that delegates to the method
2007      * of the same name on the list's selection model.
2008      *
2009      * @param index index to be queried for selection state
2010      * @return {@code true} if the specified index is selected,
2011      *         else {@code false}
2012      * @see ListSelectionModel#isSelectedIndex
2013      * @see #setSelectedIndex
2014      */
2015     public boolean isSelectedIndex(int index) {
2016         return getSelectionModel().isSelectedIndex(index);
2017     }
2018 
2019 
2020     /**
2021      * Returns {@code true} if nothing is selected, else {@code false}.
2022      * This is a cover method that delegates to the method of the same
2023      * name on the list's selection model.
2024      *
2025      * @return {@code true} if nothing is selected, else {@code false}
2026      * @see ListSelectionModel#isSelectionEmpty
2027      * @see #clearSelection
2028      */
2029     public boolean isSelectionEmpty() {
2030         return getSelectionModel().isSelectionEmpty();
2031     }
2032 
2033 
2034     /**
2035      * Clears the selection; after calling this method, {@code isSelectionEmpty}
2036      * will return {@code true}. This is a cover method that delegates to the
2037      * method of the same name on the list's selection model.
2038      *
2039      * @see ListSelectionModel#clearSelection
2040      * @see #isSelectionEmpty
2041      */
2042     public void clearSelection() {
2043         getSelectionModel().clearSelection();
2044     }
2045 
2046 
2047     /**
2048      * Selects the specified interval. Both {@code anchor} and {@code lead}
2049      * indices are included. {@code anchor} doesn't have to be less than or
2050      * equal to {@code lead}. This is a cover method that delegates to the
2051      * method of the same name on the list's selection model.
2052      * <p>
2053      * Refer to the documentation of the selection model class being used
2054      * for details on how values less than {@code 0} are handled.
2055      *
2056      * @param anchor the first index to select
2057      * @param lead the last index to select
2058      * @see ListSelectionModel#setSelectionInterval
2059      * @see DefaultListSelectionModel#setSelectionInterval
2060      * @see #createSelectionModel
2061      * @see #addSelectionInterval
2062      * @see #removeSelectionInterval
2063      */
2064     public void setSelectionInterval(int anchor, int lead) {
2065         getSelectionModel().setSelectionInterval(anchor, lead);
2066     }
2067 
2068 
2069     /**
2070      * Sets the selection to be the union of the specified interval with current
2071      * selection. Both the {@code anchor} and {@code lead} indices are
2072      * included. {@code anchor} doesn't have to be less than or
2073      * equal to {@code lead}. This is a cover method that delegates to the
2074      * method of the same name on the list's selection model.
2075      * <p>
2076      * Refer to the documentation of the selection model class being used
2077      * for details on how values less than {@code 0} are handled.
2078      *
2079      * @param anchor the first index to add to the selection
2080      * @param lead the last index to add to the selection
2081      * @see ListSelectionModel#addSelectionInterval
2082      * @see DefaultListSelectionModel#addSelectionInterval
2083      * @see #createSelectionModel
2084      * @see #setSelectionInterval
2085      * @see #removeSelectionInterval
2086      */
2087     public void addSelectionInterval(int anchor, int lead) {
2088         getSelectionModel().addSelectionInterval(anchor, lead);
2089     }
2090 
2091 
2092     /**
2093      * Sets the selection to be the set difference of the specified interval
2094      * and the current selection. Both the {@code index0} and {@code index1}
2095      * indices are removed. {@code index0} doesn't have to be less than or
2096      * equal to {@code index1}. This is a cover method that delegates to the
2097      * method of the same name on the list's selection model.
2098      * <p>
2099      * Refer to the documentation of the selection model class being used
2100      * for details on how values less than {@code 0} are handled.
2101      *
2102      * @param index0 the first index to remove from the selection
2103      * @param index1 the last index to remove from the selection
2104      * @see ListSelectionModel#removeSelectionInterval
2105      * @see DefaultListSelectionModel#removeSelectionInterval
2106      * @see #createSelectionModel
2107      * @see #setSelectionInterval
2108      * @see #addSelectionInterval
2109      */
2110     public void removeSelectionInterval(int index0, int index1) {
2111         getSelectionModel().removeSelectionInterval(index0, index1);
2112     }
2113 
2114 
2115     /**
2116      * Sets the selection model's {@code valueIsAdjusting} property. When
2117      * {@code true}, upcoming changes to selection should be considered part
2118      * of a single change. This property is used internally and developers
2119      * typically need not call this method. For example, when the model is being
2120      * updated in response to a user drag, the value of the property is set
2121      * to {@code true} when the drag is initiated and set to {@code false}
2122      * when the drag is finished. This allows listeners to update only
2123      * when a change has been finalized, rather than handling all of the
2124      * intermediate values.
2125      * <p>
2126      * You may want to use this directly if making a series of changes
2127      * that should be considered part of a single change.
2128      * <p>
2129      * This is a cover method that delegates to the method of the same name on
2130      * the list's selection model. See the documentation for
2131      * {@link javax.swing.ListSelectionModel#setValueIsAdjusting} for
2132      * more details.
2133      *
2134      * @param b the new value for the property
2135      * @see ListSelectionModel#setValueIsAdjusting
2136      * @see javax.swing.event.ListSelectionEvent#getValueIsAdjusting
2137      * @see #getValueIsAdjusting
2138      */
2139     public void setValueIsAdjusting(boolean b) {
2140         getSelectionModel().setValueIsAdjusting(b);
2141     }
2142 
2143 
2144     /**
2145      * Returns the value of the selection model's {@code isAdjusting} property.
2146      * <p>
2147      * This is a cover method that delegates to the method of the same name on
2148      * the list's selection model.
2149      *
2150      * @return the value of the selection model's {@code isAdjusting} property.
2151      *
2152      * @see #setValueIsAdjusting
2153      * @see ListSelectionModel#getValueIsAdjusting
2154      */
2155     public boolean getValueIsAdjusting() {
2156         return getSelectionModel().getValueIsAdjusting();
2157     }
2158 
2159 
2160     /**
2161      * Returns an array of all of the selected indices, in increasing
2162      * order.
2163      *
2164      * @return all of the selected indices, in increasing order,
2165      *         or an empty array if nothing is selected
2166      * @see #removeSelectionInterval
2167      * @see #addListSelectionListener
2168      */
2169     @Transient
2170     public int[] getSelectedIndices() {
2171         ListSelectionModel sm = getSelectionModel();
2172         int iMin = sm.getMinSelectionIndex();
2173         int iMax = sm.getMaxSelectionIndex();
2174 
2175         if ((iMin < 0) || (iMax < 0)) {
2176             return new int[0];
2177         }
2178 
2179         int[] rvTmp = new int[1+ (iMax - iMin)];
2180         int n = 0;
2181         for(int i = iMin; i <= iMax; i++) {
2182             if (sm.isSelectedIndex(i)) {
2183                 rvTmp[n++] = i;
2184             }
2185         }
2186         int[] rv = new int[n];
2187         System.arraycopy(rvTmp, 0, rv, 0, n);
2188         return rv;
2189     }
2190 
2191 
2192     /**
2193      * Selects a single cell. Does nothing if the given index is greater
2194      * than or equal to the model size. This is a convenience method that uses
2195      * {@code setSelectionInterval} on the selection model. Refer to the
2196      * documentation for the selection model class being used for details on
2197      * how values less than {@code 0} are handled.
2198      *
2199      * @param index the index of the cell to select
2200      * @see ListSelectionModel#setSelectionInterval
2201      * @see #isSelectedIndex
2202      * @see #addListSelectionListener
2203      * @beaninfo
2204      * description: The index of the selected cell.
2205      */
2206     public void setSelectedIndex(int index) {
2207         if (index >= getModel().getSize()) {
2208             return;
2209         }
2210         getSelectionModel().setSelectionInterval(index, index);
2211     }
2212 
2213 
2214     /**
2215      * Changes the selection to be the set of indices specified by the given
2216      * array. Indices greater than or equal to the model size are ignored.
2217      * This is a convenience method that clears the selection and then uses
2218      * {@code addSelectionInterval} on the selection model to add the indices.
2219      * Refer to the documentation of the selection model class being used for
2220      * details on how values less than {@code 0} are handled.
2221      *
2222      * @param indices an array of the indices of the cells to select,
2223      *                {@code non-null}
2224      * @see ListSelectionModel#addSelectionInterval
2225      * @see #isSelectedIndex
2226      * @see #addListSelectionListener
2227      * @throws NullPointerException if the given array is {@code null}
2228      */
2229     public void setSelectedIndices(int[] indices) {
2230         ListSelectionModel sm = getSelectionModel();
2231         sm.clearSelection();
2232         int size = getModel().getSize();
2233         for (int i : indices) {
2234             if (i < size) {
2235                 sm.addSelectionInterval(i, i);
2236             }
2237         }
2238     }
2239 
2240 
2241     /**
2242      * Returns an array of all the selected values, in increasing order based
2243      * on their indices in the list.
2244      *
2245      * @return the selected values, or an empty array if nothing is selected
2246      * @see #isSelectedIndex
2247      * @see #getModel
2248      * @see #addListSelectionListener
2249      *
2250      * @deprecated As of JDK 1.7, replaced by {@link #getSelectedValuesList()}
2251      */
2252     @Deprecated
2253     public Object[] getSelectedValues() {
2254         ListSelectionModel sm = getSelectionModel();
2255         ListModel<E> dm = getModel();
2256 
2257         int iMin = sm.getMinSelectionIndex();
2258         int iMax = sm.getMaxSelectionIndex();
2259 
2260         if ((iMin < 0) || (iMax < 0)) {
2261             return new Object[0];
2262         }
2263 
2264         Object[] rvTmp = new Object[1+ (iMax - iMin)];
2265         int n = 0;
2266         for(int i = iMin; i <= iMax; i++) {
2267             if (sm.isSelectedIndex(i)) {
2268                 rvTmp[n++] = dm.getElementAt(i);
2269             }
2270         }
2271         Object[] rv = new Object[n];
2272         System.arraycopy(rvTmp, 0, rv, 0, n);
2273         return rv;
2274     }
2275 
2276     /**
2277      * Returns a list of all the selected items, in increasing order based
2278      * on their indices in the list.
2279      *
2280      * @return the selected items, or an empty list if nothing is selected
2281      * @see #isSelectedIndex
2282      * @see #getModel
2283      * @see #addListSelectionListener
2284      *
2285      * @since 1.7
2286      */
2287     public List<E> getSelectedValuesList() {
2288         ListSelectionModel sm = getSelectionModel();
2289         ListModel<E> dm = getModel();
2290 
2291         int iMin = sm.getMinSelectionIndex();
2292         int iMax = sm.getMaxSelectionIndex();
2293 
2294         if ((iMin < 0) || (iMax < 0)) {
2295             return Collections.emptyList();
2296         }
2297 
2298         List<E> selectedItems = new ArrayList<E>();
2299         for(int i = iMin; i <= iMax; i++) {
2300             if (sm.isSelectedIndex(i)) {
2301                 selectedItems.add(dm.getElementAt(i));
2302             }
2303         }
2304         return selectedItems;
2305     }
2306 
2307 
2308     /**
2309      * Returns the smallest selected cell index; <i>the selection</i> when only
2310      * a single item is selected in the list. When multiple items are selected,
2311      * it is simply the smallest selected index. Returns {@code -1} if there is
2312      * no selection.
2313      * <p>
2314      * This method is a cover that delegates to {@code getMinSelectionIndex}.
2315      *
2316      * @return the smallest selected cell index
2317      * @see #getMinSelectionIndex
2318      * @see #addListSelectionListener
2319      */
2320     public int getSelectedIndex() {
2321         return getMinSelectionIndex();
2322     }
2323 
2324 
2325     /**
2326      * Returns the value for the smallest selected cell index;
2327      * <i>the selected value</i> when only a single item is selected in the
2328      * list. When multiple items are selected, it is simply the value for the
2329      * smallest selected index. Returns {@code null} if there is no selection.
2330      * <p>
2331      * This is a convenience method that simply returns the model value for
2332      * {@code getMinSelectionIndex}.
2333      *
2334      * @return the first selected value
2335      * @see #getMinSelectionIndex
2336      * @see #getModel
2337      * @see #addListSelectionListener
2338      */
2339     public E getSelectedValue() {
2340         int i = getMinSelectionIndex();
2341         return (i == -1) ? null : getModel().getElementAt(i);
2342     }
2343 
2344 
2345     /**
2346      * Selects the specified object from the list.
2347      *
2348      * @param anObject      the object to select
2349      * @param shouldScroll  {@code true} if the list should scroll to display
2350      *                      the selected object, if one exists; otherwise {@code false}
2351      */
2352     public void setSelectedValue(Object anObject,boolean shouldScroll) {
2353         if(anObject == null)
2354             setSelectedIndex(-1);
2355         else if(!anObject.equals(getSelectedValue())) {
2356             int i,c;
2357             ListModel<E> dm = getModel();
2358             for(i=0,c=dm.getSize();i<c;i++)
2359                 if(anObject.equals(dm.getElementAt(i))){
2360                     setSelectedIndex(i);
2361                     if(shouldScroll)
2362                         ensureIndexIsVisible(i);
2363                     repaint();  /** FIX-ME setSelectedIndex does not redraw all the time with the basic l&f**/
2364                     return;
2365                 }
2366             setSelectedIndex(-1);
2367         }
2368         repaint(); /** FIX-ME setSelectedIndex does not redraw all the time with the basic l&f**/
2369     }
2370 
2371 
2372 
2373     /**
2374      * --- The Scrollable Implementation ---
2375      */
2376 
2377     private void checkScrollableParameters(Rectangle visibleRect, int orientation) {
2378         if (visibleRect == null) {
2379             throw new IllegalArgumentException("visibleRect must be non-null");
2380         }
2381         switch (orientation) {
2382         case SwingConstants.VERTICAL:
2383         case SwingConstants.HORIZONTAL:
2384             break;
2385         default:
2386             throw new IllegalArgumentException("orientation must be one of: VERTICAL, HORIZONTAL");
2387         }
2388     }
2389 
2390 
2391     /**
2392      * Computes the size of viewport needed to display {@code visibleRowCount}
2393      * rows. The value returned by this method depends on the layout
2394      * orientation:
2395      * <p>
2396      * <b>{@code VERTICAL}:</b>
2397      * <br>
2398      * This is trivial if both {@code fixedCellWidth} and {@code fixedCellHeight}
2399      * have been set (either explicitly or by specifying a prototype cell value).
2400      * The width is simply the {@code fixedCellWidth} plus the list's horizontal
2401      * insets. The height is the {@code fixedCellHeight} multiplied by the
2402      * {@code visibleRowCount}, plus the list's vertical insets.
2403      * <p>
2404      * If either {@code fixedCellWidth} or {@code fixedCellHeight} haven't been
2405      * specified, heuristics are used. If the model is empty, the width is
2406      * the {@code fixedCellWidth}, if greater than {@code 0}, or a hard-coded
2407      * value of {@code 256}. The height is the {@code fixedCellHeight} multiplied
2408      * by {@code visibleRowCount}, if {@code fixedCellHeight} is greater than
2409      * {@code 0}, otherwise it is a hard-coded value of {@code 16} multiplied by
2410      * {@code visibleRowCount}.
2411      * <p>
2412      * If the model isn't empty, the width is the preferred size's width,
2413      * typically the width of the widest list element. The height is the
2414      * {@code fixedCellHeight} multiplied by the {@code visibleRowCount},
2415      * plus the list's vertical insets.
2416      * <p>
2417      * <b>{@code VERTICAL_WRAP} or {@code HORIZONTAL_WRAP}:</b>
2418      * <br>
2419      * This method simply returns the value from {@code getPreferredSize}.
2420      * The list's {@code ListUI} is expected to override {@code getPreferredSize}
2421      * to return an appropriate value.
2422      *
2423      * @return a dimension containing the size of the viewport needed
2424      *          to display {@code visibleRowCount} rows
2425      * @see #getPreferredScrollableViewportSize
2426      * @see #setPrototypeCellValue
2427      */
2428     public Dimension getPreferredScrollableViewportSize()
2429     {
2430         if (getLayoutOrientation() != VERTICAL) {
2431             return getPreferredSize();
2432         }
2433         Insets insets = getInsets();
2434         int dx = insets.left + insets.right;
2435         int dy = insets.top + insets.bottom;
2436 
2437         int visibleRowCount = getVisibleRowCount();
2438         int fixedCellWidth = getFixedCellWidth();
2439         int fixedCellHeight = getFixedCellHeight();
2440 
2441         if ((fixedCellWidth > 0) && (fixedCellHeight > 0)) {
2442             int width = fixedCellWidth + dx;
2443             int height = (visibleRowCount * fixedCellHeight) + dy;
2444             return new Dimension(width, height);
2445         }
2446         else if (getModel().getSize() > 0) {
2447             int width = getPreferredSize().width;
2448             int height;
2449             Rectangle r = getCellBounds(0, 0);
2450             if (r != null) {
2451                 height = (visibleRowCount * r.height) + dy;
2452             }
2453             else {
2454                 // Will only happen if UI null, shouldn't matter what we return
2455                 height = 1;
2456             }
2457             return new Dimension(width, height);
2458         }
2459         else {
2460             fixedCellWidth = (fixedCellWidth > 0) ? fixedCellWidth : 256;
2461             fixedCellHeight = (fixedCellHeight > 0) ? fixedCellHeight : 16;
2462             return new Dimension(fixedCellWidth, fixedCellHeight * visibleRowCount);
2463         }
2464     }
2465 
2466 
2467     /**
2468      * Returns the distance to scroll to expose the next or previous
2469      * row (for vertical scrolling) or column (for horizontal scrolling).
2470      * <p>
2471      * For horizontal scrolling, if the layout orientation is {@code VERTICAL},
2472      * then the list's font size is returned (or {@code 1} if the font is
2473      * {@code null}).
2474      *
2475      * @param visibleRect the view area visible within the viewport
2476      * @param orientation {@code SwingConstants.HORIZONTAL} or
2477      *                    {@code SwingConstants.VERTICAL}
2478      * @param direction less or equal to zero to scroll up/back,
2479      *                  greater than zero for down/forward
2480      * @return the "unit" increment for scrolling in the specified direction;
2481      *         always positive
2482      * @see #getScrollableBlockIncrement
2483      * @see Scrollable#getScrollableUnitIncrement
2484      * @throws IllegalArgumentException if {@code visibleRect} is {@code null}, or
2485      *         {@code orientation} isn't one of {@code SwingConstants.VERTICAL} or
2486      *         {@code SwingConstants.HORIZONTAL}
2487      */
2488     public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction)
2489     {
2490         checkScrollableParameters(visibleRect, orientation);
2491 
2492         if (orientation == SwingConstants.VERTICAL) {
2493             int row = locationToIndex(visibleRect.getLocation());
2494 
2495             if (row == -1) {
2496                 return 0;
2497             }
2498             else {
2499                 /* Scroll Down */
2500                 if (direction > 0) {
2501                     Rectangle r = getCellBounds(row, row);
2502                     return (r == null) ? 0 : r.height - (visibleRect.y - r.y);
2503                 }
2504                 /* Scroll Up */
2505                 else {
2506                     Rectangle r = getCellBounds(row, row);
2507 
2508                     /* The first row is completely visible and it's row 0.
2509                      * We're done.
2510                      */
2511                     if ((r.y == visibleRect.y) && (row == 0))  {
2512                         return 0;
2513                     }
2514                     /* The first row is completely visible, return the
2515                      * height of the previous row or 0 if the first row
2516                      * is the top row of the list.
2517                      */
2518                     else if (r.y == visibleRect.y) {
2519                         Point loc = r.getLocation();
2520                         loc.y--;
2521                         int prevIndex = locationToIndex(loc);
2522                         Rectangle prevR = getCellBounds(prevIndex, prevIndex);
2523 
2524                         if (prevR == null || prevR.y >= r.y) {
2525                             return 0;
2526                         }
2527                         return prevR.height;
2528                     }
2529                     /* The first row is partially visible, return the
2530                      * height of hidden part.
2531                      */
2532                     else {
2533                         return visibleRect.y - r.y;
2534                     }
2535                 }
2536             }
2537         } else if (orientation == SwingConstants.HORIZONTAL &&
2538                            getLayoutOrientation() != JList.VERTICAL) {
2539             boolean leftToRight = getComponentOrientation().isLeftToRight();
2540             int index;
2541             Point leadingPoint;
2542 
2543             if (leftToRight) {
2544                 leadingPoint = visibleRect.getLocation();
2545             }
2546             else {
2547                 leadingPoint = new Point(visibleRect.x + visibleRect.width -1,
2548                                          visibleRect.y);
2549             }
2550             index = locationToIndex(leadingPoint);
2551 
2552             if (index != -1) {
2553                 Rectangle cellBounds = getCellBounds(index, index);
2554                 if (cellBounds != null && cellBounds.contains(leadingPoint)) {
2555                     int leadingVisibleEdge;
2556                     int leadingCellEdge;
2557 
2558                     if (leftToRight) {
2559                         leadingVisibleEdge = visibleRect.x;
2560                         leadingCellEdge = cellBounds.x;
2561                     }
2562                     else {
2563                         leadingVisibleEdge = visibleRect.x + visibleRect.width;
2564                         leadingCellEdge = cellBounds.x + cellBounds.width;
2565                     }
2566 
2567                     if (leadingCellEdge != leadingVisibleEdge) {
2568                         if (direction < 0) {
2569                             // Show remainder of leading cell
2570                             return Math.abs(leadingVisibleEdge - leadingCellEdge);
2571 
2572                         }
2573                         else if (leftToRight) {
2574                             // Hide rest of leading cell
2575                             return leadingCellEdge + cellBounds.width - leadingVisibleEdge;
2576                         }
2577                         else {
2578                             // Hide rest of leading cell
2579                             return leadingVisibleEdge - cellBounds.x;
2580                         }
2581                     }
2582                     // ASSUME: All cells are the same width
2583                     return cellBounds.width;
2584                 }
2585             }
2586         }
2587         Font f = getFont();
2588         return (f != null) ? f.getSize() : 1;
2589     }
2590 
2591 
2592     /**
2593      * Returns the distance to scroll to expose the next or previous block.
2594      * <p>
2595      * For vertical scrolling, the following rules are used:
2596      * <ul>
2597      * <li>if scrolling down, returns the distance to scroll so that the last
2598      * visible element becomes the first completely visible element
2599      * <li>if scrolling up, returns the distance to scroll so that the first
2600      * visible element becomes the last completely visible element
2601      * <li>returns {@code visibleRect.height} if the list is empty
2602      * </ul>
2603      * <p>
2604      * For horizontal scrolling, when the layout orientation is either
2605      * {@code VERTICAL_WRAP} or {@code HORIZONTAL_WRAP}:
2606      * <ul>
2607      * <li>if scrolling right, returns the distance to scroll so that the
2608      * last visible element becomes
2609      * the first completely visible element
2610      * <li>if scrolling left, returns the distance to scroll so that the first
2611      * visible element becomes the last completely visible element
2612      * <li>returns {@code visibleRect.width} if the list is empty
2613      * </ul>
2614      * <p>
2615      * For horizontal scrolling and {@code VERTICAL} orientation,
2616      * returns {@code visibleRect.width}.
2617      * <p>
2618      * Note that the value of {@code visibleRect} must be the equal to
2619      * {@code this.getVisibleRect()}.
2620      *
2621      * @param visibleRect the view area visible within the viewport
2622      * @param orientation {@code SwingConstants.HORIZONTAL} or
2623      *                    {@code SwingConstants.VERTICAL}
2624      * @param direction less or equal to zero to scroll up/back,
2625      *                  greater than zero for down/forward
2626      * @return the "block" increment for scrolling in the specified direction;
2627      *         always positive
2628      * @see #getScrollableUnitIncrement
2629      * @see Scrollable#getScrollableBlockIncrement
2630      * @throws IllegalArgumentException if {@code visibleRect} is {@code null}, or
2631      *         {@code orientation} isn't one of {@code SwingConstants.VERTICAL} or
2632      *         {@code SwingConstants.HORIZONTAL}
2633      */
2634     public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
2635         checkScrollableParameters(visibleRect, orientation);
2636         if (orientation == SwingConstants.VERTICAL) {
2637             int inc = visibleRect.height;
2638             /* Scroll Down */
2639             if (direction > 0) {
2640                 // last cell is the lowest left cell
2641                 int last = locationToIndex(new Point(visibleRect.x, visibleRect.y+visibleRect.height-1));
2642                 if (last != -1) {
2643                     Rectangle lastRect = getCellBounds(last,last);
2644                     if (lastRect != null) {
2645                         inc = lastRect.y - visibleRect.y;
2646                         if ( (inc == 0) && (last < getModel().getSize()-1) ) {
2647                             inc = lastRect.height;
2648                         }
2649                     }
2650                 }
2651             }
2652             /* Scroll Up */
2653             else {
2654                 int newFirst = locationToIndex(new Point(visibleRect.x, visibleRect.y-visibleRect.height));
2655                 int first = getFirstVisibleIndex();
2656                 if (newFirst != -1) {
2657                     if (first == -1) {
2658                         first = locationToIndex(visibleRect.getLocation());
2659                     }
2660                     Rectangle newFirstRect = getCellBounds(newFirst,newFirst);
2661                     Rectangle firstRect = getCellBounds(first,first);
2662                     if ((newFirstRect != null) && (firstRect!=null)) {
2663                         while ( (newFirstRect.y + visibleRect.height <
2664                                  firstRect.y + firstRect.height) &&
2665                                 (newFirstRect.y < firstRect.y) ) {
2666                             newFirst++;
2667                             newFirstRect = getCellBounds(newFirst,newFirst);
2668                         }
2669                         inc = visibleRect.y - newFirstRect.y;
2670                         if ( (inc <= 0) && (newFirstRect.y > 0)) {
2671                             newFirst--;
2672                             newFirstRect = getCellBounds(newFirst,newFirst);
2673                             if (newFirstRect != null) {
2674                                 inc = visibleRect.y - newFirstRect.y;
2675                             }
2676                         }
2677                     }
2678                 }
2679             }
2680             return inc;
2681         }
2682         else if (orientation == SwingConstants.HORIZONTAL &&
2683                  getLayoutOrientation() != JList.VERTICAL) {
2684             boolean leftToRight = getComponentOrientation().isLeftToRight();
2685             int inc = visibleRect.width;
2686             /* Scroll Right (in ltr mode) or Scroll Left (in rtl mode) */
2687             if (direction > 0) {
2688                 // position is upper right if ltr, or upper left otherwise
2689                 int x = visibleRect.x + (leftToRight ? (visibleRect.width - 1) : 0);
2690                 int last = locationToIndex(new Point(x, visibleRect.y));
2691 
2692                 if (last != -1) {
2693                     Rectangle lastRect = getCellBounds(last,last);
2694                     if (lastRect != null) {
2695                         if (leftToRight) {
2696                             inc = lastRect.x - visibleRect.x;
2697                         } else {
2698                             inc = visibleRect.x + visibleRect.width
2699                                       - (lastRect.x + lastRect.width);
2700                         }
2701                         if (inc < 0) {
2702                             inc += lastRect.width;
2703                         } else if ( (inc == 0) && (last < getModel().getSize()-1) ) {
2704                             inc = lastRect.width;
2705                         }
2706                     }
2707                 }
2708             }
2709             /* Scroll Left (in ltr mode) or Scroll Right (in rtl mode) */
2710             else {
2711                 // position is upper left corner of the visibleRect shifted
2712                 // left by the visibleRect.width if ltr, or upper right shifted
2713                 // right by the visibleRect.width otherwise
2714                 int x = visibleRect.x + (leftToRight
2715                                          ? -visibleRect.width
2716                                          : visibleRect.width - 1 + visibleRect.width);
2717                 int first = locationToIndex(new Point(x, visibleRect.y));
2718 
2719                 if (first != -1) {
2720                     Rectangle firstRect = getCellBounds(first,first);
2721                     if (firstRect != null) {
2722                         // the right of the first cell
2723                         int firstRight = firstRect.x + firstRect.width;
2724 
2725                         if (leftToRight) {
2726                             if ((firstRect.x < visibleRect.x - visibleRect.width)
2727                                     && (firstRight < visibleRect.x)) {
2728                                 inc = visibleRect.x - firstRight;
2729                             } else {
2730                                 inc = visibleRect.x - firstRect.x;
2731                             }
2732                         } else {
2733                             int visibleRight = visibleRect.x + visibleRect.width;
2734 
2735                             if ((firstRight > visibleRight + visibleRect.width)
2736                                     && (firstRect.x > visibleRight)) {
2737                                 inc = firstRect.x - visibleRight;
2738                             } else {
2739                                 inc = firstRight - visibleRight;
2740                             }
2741                         }
2742                     }
2743                 }
2744             }
2745             return inc;
2746         }
2747         return visibleRect.width;
2748     }
2749 
2750 
2751     /**
2752      * Returns {@code true} if this {@code JList} is displayed in a
2753      * {@code JViewport} and the viewport is wider than the list's
2754      * preferred width, or if the layout orientation is {@code HORIZONTAL_WRAP}
2755      * and {@code visibleRowCount <= 0}; otherwise returns {@code false}.
2756      * <p>
2757      * If {@code false}, then don't track the viewport's width. This allows
2758      * horizontal scrolling if the {@code JViewport} is itself embedded in a
2759      * {@code JScrollPane}.
2760      *
2761      * @return whether or not an enclosing viewport should force the list's
2762      *         width to match its own
2763      * @see Scrollable#getScrollableTracksViewportWidth
2764      */
2765     public boolean getScrollableTracksViewportWidth() {
2766         if (getLayoutOrientation() == HORIZONTAL_WRAP &&
2767                                       getVisibleRowCount() <= 0) {
2768             return true;
2769         }
2770         Container parent = SwingUtilities.getUnwrappedParent(this);
2771         if (parent instanceof JViewport) {
2772             return parent.getWidth() > getPreferredSize().width;
2773         }
2774         return false;
2775     }
2776 
2777     /**
2778      * Returns {@code true} if this {@code JList} is displayed in a
2779      * {@code JViewport} and the viewport is taller than the list's
2780      * preferred height, or if the layout orientation is {@code VERTICAL_WRAP}
2781      * and {@code visibleRowCount <= 0}; otherwise returns {@code false}.
2782      * <p>
2783      * If {@code false}, then don't track the viewport's height. This allows
2784      * vertical scrolling if the {@code JViewport} is itself embedded in a
2785      * {@code JScrollPane}.
2786      *
2787      * @return whether or not an enclosing viewport should force the list's
2788      *         height to match its own
2789      * @see Scrollable#getScrollableTracksViewportHeight
2790      */
2791     public boolean getScrollableTracksViewportHeight() {
2792         if (getLayoutOrientation() == VERTICAL_WRAP &&
2793                      getVisibleRowCount() <= 0) {
2794             return true;
2795         }
2796         Container parent = SwingUtilities.getUnwrappedParent(this);
2797         if (parent instanceof JViewport) {
2798             return parent.getHeight() > getPreferredSize().height;
2799         }
2800         return false;
2801     }
2802 
2803 
2804     /*
2805      * See {@code readObject} and {@code writeObject} in {@code JComponent}
2806      * for more information about serialization in Swing.
2807      */
2808     private void writeObject(ObjectOutputStream s) throws IOException {
2809         s.defaultWriteObject();
2810         if (getUIClassID().equals(uiClassID)) {
2811             byte count = JComponent.getWriteObjCounter(this);
2812             JComponent.setWriteObjCounter(this, --count);
2813             if (count == 0 && ui != null) {
2814                 ui.installUI(this);
2815             }
2816         }
2817     }
2818 
2819 
2820     /**
2821      * Returns a {@code String} representation of this {@code JList}.
2822      * This method is intended to be used only for debugging purposes,
2823      * and the content and format of the returned {@code String} may vary
2824      * between implementations. The returned {@code String} may be empty,
2825      * but may not be {@code null}.
2826      *
2827      * @return  a {@code String} representation of this {@code JList}.
2828      */
2829     protected String paramString() {
2830         String selectionForegroundString = (selectionForeground != null ?
2831                                             selectionForeground.toString() :
2832                                             "");
2833         String selectionBackgroundString = (selectionBackground != null ?
2834                                             selectionBackground.toString() :
2835                                             "");
2836 
2837         return super.paramString() +
2838         ",fixedCellHeight=" + fixedCellHeight +
2839         ",fixedCellWidth=" + fixedCellWidth +
2840         ",horizontalScrollIncrement=" + horizontalScrollIncrement +
2841         ",selectionBackground=" + selectionBackgroundString +
2842         ",selectionForeground=" + selectionForegroundString +
2843         ",visibleRowCount=" + visibleRowCount +
2844         ",layoutOrientation=" + layoutOrientation;
2845     }
2846 
2847 
2848     /**
2849      * --- Accessibility Support ---
2850      */
2851 
2852     /**
2853      * Gets the {@code AccessibleContext} associated with this {@code JList}.
2854      * For {@code JList}, the {@code AccessibleContext} takes the form of an
2855      * {@code AccessibleJList}.
2856      * <p>
2857      * A new {@code AccessibleJList} instance is created if necessary.
2858      *
2859      * @return an {@code AccessibleJList} that serves as the
2860      *         {@code AccessibleContext} of this {@code JList}
2861      */
2862     public AccessibleContext getAccessibleContext() {
2863         if (accessibleContext == null) {
2864             accessibleContext = new AccessibleJList();
2865         }
2866         return accessibleContext;
2867     }
2868 
2869     /**
2870      * This class implements accessibility support for the
2871      * {@code JList} class. It provides an implementation of the
2872      * Java Accessibility API appropriate to list user-interface
2873      * elements.
2874      * <p>
2875      * <strong>Warning:</strong>
2876      * Serialized objects of this class will not be compatible with
2877      * future Swing releases. The current serialization support is
2878      * appropriate for short term storage or RMI between applications running
2879      * the same version of Swing.  As of 1.4, support for long term storage
2880      * of all JavaBeans&trade;
2881      * has been added to the <code>java.beans</code> package.
2882      * Please see {@link java.beans.XMLEncoder}.
2883      */
2884     protected class AccessibleJList extends AccessibleJComponent
2885         implements AccessibleSelection, PropertyChangeListener,
2886         ListSelectionListener, ListDataListener {
2887 
2888         int leadSelectionIndex;
2889 
2890         public AccessibleJList() {
2891             super();
2892             JList.this.addPropertyChangeListener(this);
2893             JList.this.getSelectionModel().addListSelectionListener(this);
2894             JList.this.getModel().addListDataListener(this);
2895             leadSelectionIndex = JList.this.getLeadSelectionIndex();
2896         }
2897 
2898         /**
2899          * Property Change Listener change method. Used to track changes
2900          * to the DataModel and ListSelectionModel, in order to re-set
2901          * listeners to those for reporting changes there via the Accessibility
2902          * PropertyChange mechanism.
2903          *
2904          * @param e PropertyChangeEvent
2905          */
2906         public void propertyChange(PropertyChangeEvent e) {
2907             String name = e.getPropertyName();
2908             Object oldValue = e.getOldValue();
2909             Object newValue = e.getNewValue();
2910 
2911                 // re-set listData listeners
2912             if (name.compareTo("model") == 0) {
2913 
2914                 if (oldValue != null && oldValue instanceof ListModel) {
2915                     ((ListModel) oldValue).removeListDataListener(this);
2916                 }
2917                 if (newValue != null && newValue instanceof ListModel) {
2918                     ((ListModel) newValue).addListDataListener(this);
2919                 }
2920 
2921                 // re-set listSelectionModel listeners
2922             } else if (name.compareTo("selectionModel") == 0) {
2923 
2924                 if (oldValue != null && oldValue instanceof ListSelectionModel) {
2925                     ((ListSelectionModel) oldValue).removeListSelectionListener(this);
2926                 }
2927                 if (newValue != null && newValue instanceof ListSelectionModel) {
2928                     ((ListSelectionModel) newValue).addListSelectionListener(this);
2929                 }
2930 
2931                 firePropertyChange(
2932                     AccessibleContext.ACCESSIBLE_SELECTION_PROPERTY,
2933                     Boolean.valueOf(false), Boolean.valueOf(true));
2934             }
2935         }
2936 
2937         /**
2938          * List Selection Listener value change method. Used to fire
2939          * the property change
2940          *
2941          * @param e ListSelectionEvent
2942          *
2943          */
2944         public void valueChanged(ListSelectionEvent e) {
2945             int oldLeadSelectionIndex = leadSelectionIndex;
2946             leadSelectionIndex = JList.this.getLeadSelectionIndex();
2947             if (oldLeadSelectionIndex != leadSelectionIndex) {
2948                 Accessible oldLS, newLS;
2949                 oldLS = (oldLeadSelectionIndex >= 0)
2950                         ? getAccessibleChild(oldLeadSelectionIndex)
2951                         : null;
2952                 newLS = (leadSelectionIndex >= 0)
2953                         ? getAccessibleChild(leadSelectionIndex)
2954                         : null;
2955                 firePropertyChange(AccessibleContext.ACCESSIBLE_ACTIVE_DESCENDANT_PROPERTY,
2956                                    oldLS, newLS);
2957             }
2958 
2959             firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
2960                                Boolean.valueOf(false), Boolean.valueOf(true));
2961             firePropertyChange(AccessibleContext.ACCESSIBLE_SELECTION_PROPERTY,
2962                                Boolean.valueOf(false), Boolean.valueOf(true));
2963 
2964             // Process the State changes for Multiselectable
2965             AccessibleStateSet s = getAccessibleStateSet();
2966             ListSelectionModel lsm = JList.this.getSelectionModel();
2967             if (lsm.getSelectionMode() != ListSelectionModel.SINGLE_SELECTION) {
2968                 if (!s.contains(AccessibleState.MULTISELECTABLE)) {
2969                     s.add(AccessibleState.MULTISELECTABLE);
2970                     firePropertyChange(AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
2971                                        null, AccessibleState.MULTISELECTABLE);
2972                 }
2973             } else {
2974                 if (s.contains(AccessibleState.MULTISELECTABLE)) {
2975                     s.remove(AccessibleState.MULTISELECTABLE);
2976                     firePropertyChange(AccessibleContext.ACCESSIBLE_STATE_PROPERTY,
2977                                        AccessibleState.MULTISELECTABLE, null);
2978                 }
2979             }
2980         }
2981 
2982         /**
2983          * List Data Listener interval added method. Used to fire the visible data property change
2984          *
2985          * @param e ListDataEvent
2986          *
2987          */
2988         public void intervalAdded(ListDataEvent e) {
2989             firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
2990                                Boolean.valueOf(false), Boolean.valueOf(true));
2991         }
2992 
2993         /**
2994          * List Data Listener interval removed method. Used to fire the visible data property change
2995          *
2996          * @param e ListDataEvent
2997          *
2998          */
2999         public void intervalRemoved(ListDataEvent e) {
3000             firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
3001                                Boolean.valueOf(false), Boolean.valueOf(true));
3002         }
3003 
3004         /**
3005          * List Data Listener contents changed method. Used to fire the visible data property change
3006          *
3007          * @param e ListDataEvent
3008          *
3009          */
3010          public void contentsChanged(ListDataEvent e) {
3011              firePropertyChange(AccessibleContext.ACCESSIBLE_VISIBLE_DATA_PROPERTY,
3012                                 Boolean.valueOf(false), Boolean.valueOf(true));
3013          }
3014 
3015     // AccessibleContext methods
3016 
3017         /**
3018          * Get the state set of this object.
3019          *
3020          * @return an instance of AccessibleState containing the current state
3021          * of the object
3022          * @see AccessibleState
3023          */
3024         public AccessibleStateSet getAccessibleStateSet() {
3025             AccessibleStateSet states = super.getAccessibleStateSet();
3026             if (selectionModel.getSelectionMode() !=
3027                 ListSelectionModel.SINGLE_SELECTION) {
3028                 states.add(AccessibleState.MULTISELECTABLE);
3029             }
3030             return states;
3031         }
3032 
3033         /**
3034          * Get the role of this object.
3035          *
3036          * @return an instance of AccessibleRole describing the role of the
3037          * object
3038          * @see AccessibleRole
3039          */
3040         public AccessibleRole getAccessibleRole() {
3041             return AccessibleRole.LIST;
3042         }
3043 
3044         /**
3045          * Returns the <code>Accessible</code> child contained at
3046          * the local coordinate <code>Point</code>, if one exists.
3047          * Otherwise returns <code>null</code>.
3048          *
3049          * @return the <code>Accessible</code> at the specified
3050          *    location, if it exists
3051          */
3052         public Accessible getAccessibleAt(Point p) {
3053             int i = locationToIndex(p);
3054             if (i >= 0) {
3055                 return new AccessibleJListChild(JList.this, i);
3056             } else {
3057                 return null;
3058             }
3059         }
3060 
3061         /**
3062          * Returns the number of accessible children in the object.  If all
3063          * of the children of this object implement Accessible, than this
3064          * method should return the number of children of this object.
3065          *
3066          * @return the number of accessible children in the object.
3067          */
3068         public int getAccessibleChildrenCount() {
3069             return getModel().getSize();
3070         }
3071 
3072         /**
3073          * Return the nth Accessible child of the object.
3074          *
3075          * @param i zero-based index of child
3076          * @return the nth Accessible child of the object
3077          */
3078         public Accessible getAccessibleChild(int i) {
3079             if (i >= getModel().getSize()) {
3080                 return null;
3081             } else {
3082                 return new AccessibleJListChild(JList.this, i);
3083             }
3084         }
3085 
3086         /**
3087          * Get the AccessibleSelection associated with this object.  In the
3088          * implementation of the Java Accessibility API for this class,
3089          * return this object, which is responsible for implementing the
3090          * AccessibleSelection interface on behalf of itself.
3091          *
3092          * @return this object
3093          */
3094         public AccessibleSelection getAccessibleSelection() {
3095             return this;
3096         }
3097 
3098 
3099     // AccessibleSelection methods
3100 
3101         /**
3102          * Returns the number of items currently selected.
3103          * If no items are selected, the return value will be 0.
3104          *
3105          * @return the number of items currently selected.
3106          */
3107          public int getAccessibleSelectionCount() {
3108              return JList.this.getSelectedIndices().length;
3109          }
3110 
3111         /**
3112          * Returns an Accessible representing the specified selected item
3113          * in the object.  If there isn't a selection, or there are
3114          * fewer items selected than the integer passed in, the return
3115          * value will be <code>null</code>.
3116          *
3117          * @param i the zero-based index of selected items
3118          * @return an Accessible containing the selected item
3119          */
3120          public Accessible getAccessibleSelection(int i) {
3121              int len = getAccessibleSelectionCount();
3122              if (i < 0 || i >= len) {
3123                  return null;
3124              } else {
3125                  return getAccessibleChild(JList.this.getSelectedIndices()[i]);
3126              }
3127          }
3128 
3129         /**
3130          * Returns true if the current child of this object is selected.
3131          *
3132          * @param i the zero-based index of the child in this Accessible
3133          * object.
3134          * @see AccessibleContext#getAccessibleChild
3135          */
3136         public boolean isAccessibleChildSelected(int i) {
3137             return isSelectedIndex(i);
3138         }
3139 
3140         /**
3141          * Adds the specified selected item in the object to the object's
3142          * selection.  If the object supports multiple selections,
3143          * the specified item is added to any existing selection, otherwise
3144          * it replaces any existing selection in the object.  If the
3145          * specified item is already selected, this method has no effect.
3146          *
3147          * @param i the zero-based index of selectable items
3148          */
3149          public void addAccessibleSelection(int i) {
3150              JList.this.addSelectionInterval(i, i);
3151          }
3152 
3153         /**
3154          * Removes the specified selected item in the object from the object's
3155          * selection.  If the specified item isn't currently selected, this
3156          * method has no effect.
3157          *
3158          * @param i the zero-based index of selectable items
3159          */
3160          public void removeAccessibleSelection(int i) {
3161              JList.this.removeSelectionInterval(i, i);
3162          }
3163 
3164         /**
3165          * Clears the selection in the object, so that nothing in the
3166          * object is selected.
3167          */
3168          public void clearAccessibleSelection() {
3169              JList.this.clearSelection();
3170          }
3171 
3172         /**
3173          * Causes every selected item in the object to be selected
3174          * if the object supports multiple selections.
3175          */
3176          public void selectAllAccessibleSelection() {
3177              JList.this.addSelectionInterval(0, getAccessibleChildrenCount() -1);
3178          }
3179 
3180           /**
3181            * This class implements accessibility support appropriate
3182            * for list children.
3183            */
3184         protected class AccessibleJListChild extends AccessibleContext
3185                 implements Accessible, AccessibleComponent {
3186             private JList<E>     parent = null;
3187             private int       indexInParent;
3188             private Component component = null;
3189             private AccessibleContext accessibleContext = null;
3190             private ListModel<E> listModel;
3191             private ListCellRenderer<? super E> cellRenderer = null;
3192 
3193             public AccessibleJListChild(JList<E> parent, int indexInParent) {
3194                 this.parent = parent;
3195                 this.setAccessibleParent(parent);
3196                 this.indexInParent = indexInParent;
3197                 if (parent != null) {
3198                     listModel = parent.getModel();
3199                     cellRenderer = parent.getCellRenderer();
3200                 }
3201             }
3202 
3203             private Component getCurrentComponent() {
3204                 return getComponentAtIndex(indexInParent);
3205             }
3206 
3207             private AccessibleContext getCurrentAccessibleContext() {
3208                 Component c = getComponentAtIndex(indexInParent);
3209                 if (c instanceof Accessible) {
3210                     return c.getAccessibleContext();
3211                 } else {
3212                     return null;
3213                 }
3214             }
3215 
3216             private Component getComponentAtIndex(int index) {
3217                 if (index < 0 || index >= listModel.getSize()) {
3218                     return null;
3219                 }
3220                 if ((parent != null)
3221                         && (listModel != null)
3222                         && cellRenderer != null) {
3223                     E value = listModel.getElementAt(index);
3224                     boolean isSelected = parent.isSelectedIndex(index);
3225                     boolean isFocussed = parent.isFocusOwner()
3226                             && (index == parent.getLeadSelectionIndex());
3227                     return cellRenderer.getListCellRendererComponent(
3228                             parent,
3229                             value,
3230                             index,
3231                             isSelected,
3232                             isFocussed);
3233                 } else {
3234                     return null;
3235                 }
3236             }
3237 
3238 
3239             // Accessible Methods
3240            /**
3241             * Get the AccessibleContext for this object. In the
3242             * implementation of the Java Accessibility API for this class,
3243             * returns this object, which is its own AccessibleContext.
3244             *
3245             * @return this object
3246             */
3247             public AccessibleContext getAccessibleContext() {
3248                 return this;
3249             }
3250 
3251 
3252             // AccessibleContext methods
3253 
3254             public String getAccessibleName() {
3255                 AccessibleContext ac = getCurrentAccessibleContext();
3256                 if (ac != null) {
3257                     return ac.getAccessibleName();
3258                 } else {
3259                     return null;
3260                 }
3261             }
3262 
3263             public void setAccessibleName(String s) {
3264                 AccessibleContext ac = getCurrentAccessibleContext();
3265                 if (ac != null) {
3266                     ac.setAccessibleName(s);
3267                 }
3268             }
3269 
3270             public String getAccessibleDescription() {
3271                 AccessibleContext ac = getCurrentAccessibleContext();
3272                 if (ac != null) {
3273                     return ac.getAccessibleDescription();
3274                 } else {
3275                     return null;
3276                 }
3277             }
3278 
3279             public void setAccessibleDescription(String s) {
3280                 AccessibleContext ac = getCurrentAccessibleContext();
3281                 if (ac != null) {
3282                     ac.setAccessibleDescription(s);
3283                 }
3284             }
3285 
3286             public AccessibleRole getAccessibleRole() {
3287                 AccessibleContext ac = getCurrentAccessibleContext();
3288                 if (ac != null) {
3289                     return ac.getAccessibleRole();
3290                 } else {
3291                     return null;
3292                 }
3293             }
3294 
3295             public AccessibleStateSet getAccessibleStateSet() {
3296                 AccessibleContext ac = getCurrentAccessibleContext();
3297                 AccessibleStateSet s;
3298                 if (ac != null) {
3299                     s = ac.getAccessibleStateSet();
3300                 } else {
3301                     s = new AccessibleStateSet();
3302                 }
3303 
3304                 s.add(AccessibleState.SELECTABLE);
3305                 if (parent.isFocusOwner()
3306                     && (indexInParent == parent.getLeadSelectionIndex())) {
3307                     s.add(AccessibleState.ACTIVE);
3308                 }
3309                 if (parent.isSelectedIndex(indexInParent)) {
3310                     s.add(AccessibleState.SELECTED);
3311                 }
3312                 if (this.isShowing()) {
3313                     s.add(AccessibleState.SHOWING);
3314                 } else if (s.contains(AccessibleState.SHOWING)) {
3315                     s.remove(AccessibleState.SHOWING);
3316                 }
3317                 if (this.isVisible()) {
3318                     s.add(AccessibleState.VISIBLE);
3319                 } else if (s.contains(AccessibleState.VISIBLE)) {
3320                     s.remove(AccessibleState.VISIBLE);
3321                 }
3322                 s.add(AccessibleState.TRANSIENT); // cell-rendered
3323                 return s;
3324             }
3325 
3326             public int getAccessibleIndexInParent() {
3327                 return indexInParent;
3328             }
3329 
3330             public int getAccessibleChildrenCount() {
3331                 AccessibleContext ac = getCurrentAccessibleContext();
3332                 if (ac != null) {
3333                     return ac.getAccessibleChildrenCount();
3334                 } else {
3335                     return 0;
3336                 }
3337             }
3338 
3339             public Accessible getAccessibleChild(int i) {
3340                 AccessibleContext ac = getCurrentAccessibleContext();
3341                 if (ac != null) {
3342                     Accessible accessibleChild = ac.getAccessibleChild(i);
3343                     ac.setAccessibleParent(this);
3344                     return accessibleChild;
3345                 } else {
3346                     return null;
3347                 }
3348             }
3349 
3350             public Locale getLocale() {
3351                 AccessibleContext ac = getCurrentAccessibleContext();
3352                 if (ac != null) {
3353                     return ac.getLocale();
3354                 } else {
3355                     return null;
3356                 }
3357             }
3358 
3359             public void addPropertyChangeListener(PropertyChangeListener l) {
3360                 AccessibleContext ac = getCurrentAccessibleContext();
3361                 if (ac != null) {
3362                     ac.addPropertyChangeListener(l);
3363                 }
3364             }
3365 
3366             public void removePropertyChangeListener(PropertyChangeListener l) {
3367                 AccessibleContext ac = getCurrentAccessibleContext();
3368                 if (ac != null) {
3369                     ac.removePropertyChangeListener(l);
3370                 }
3371             }
3372 
3373             public AccessibleAction getAccessibleAction() {
3374                 return getCurrentAccessibleContext().getAccessibleAction();
3375             }
3376 
3377            /**
3378             * Get the AccessibleComponent associated with this object.  In the
3379             * implementation of the Java Accessibility API for this class,
3380             * return this object, which is responsible for implementing the
3381             * AccessibleComponent interface on behalf of itself.
3382             *
3383             * @return this object
3384             */
3385             public AccessibleComponent getAccessibleComponent() {
3386                 return this; // to override getBounds()
3387             }
3388 
3389             public AccessibleSelection getAccessibleSelection() {
3390                 return getCurrentAccessibleContext().getAccessibleSelection();
3391             }
3392 
3393             public AccessibleText getAccessibleText() {
3394                 return getCurrentAccessibleContext().getAccessibleText();
3395             }
3396 
3397             public AccessibleValue getAccessibleValue() {
3398                 return getCurrentAccessibleContext().getAccessibleValue();
3399             }
3400 
3401 
3402             // AccessibleComponent methods
3403 
3404             public Color getBackground() {
3405                 AccessibleContext ac = getCurrentAccessibleContext();
3406                 if (ac instanceof AccessibleComponent) {
3407                     return ((AccessibleComponent) ac).getBackground();
3408                 } else {
3409                     Component c = getCurrentComponent();
3410                     if (c != null) {
3411                         return c.getBackground();
3412                     } else {
3413                         return null;
3414                     }
3415                 }
3416             }
3417 
3418             public void setBackground(Color c) {
3419                 AccessibleContext ac = getCurrentAccessibleContext();
3420                 if (ac instanceof AccessibleComponent) {
3421                     ((AccessibleComponent) ac).setBackground(c);
3422                 } else {
3423                     Component cp = getCurrentComponent();
3424                     if (cp != null) {
3425                         cp.setBackground(c);
3426                     }
3427                 }
3428             }
3429 
3430             public Color getForeground() {
3431                 AccessibleContext ac = getCurrentAccessibleContext();
3432                 if (ac instanceof AccessibleComponent) {
3433                     return ((AccessibleComponent) ac).getForeground();
3434                 } else {
3435                     Component c = getCurrentComponent();
3436                     if (c != null) {
3437                         return c.getForeground();
3438                     } else {
3439                         return null;
3440                     }
3441                 }
3442             }
3443 
3444             public void setForeground(Color c) {
3445                 AccessibleContext ac = getCurrentAccessibleContext();
3446                 if (ac instanceof AccessibleComponent) {
3447                     ((AccessibleComponent) ac).setForeground(c);
3448                 } else {
3449                     Component cp = getCurrentComponent();
3450                     if (cp != null) {
3451                         cp.setForeground(c);
3452                     }
3453                 }
3454             }
3455 
3456             public Cursor getCursor() {
3457                 AccessibleContext ac = getCurrentAccessibleContext();
3458                 if (ac instanceof AccessibleComponent) {
3459                     return ((AccessibleComponent) ac).getCursor();
3460                 } else {
3461                     Component c = getCurrentComponent();
3462                     if (c != null) {
3463                         return c.getCursor();
3464                     } else {
3465                         Accessible ap = getAccessibleParent();
3466                         if (ap instanceof AccessibleComponent) {
3467                             return ((AccessibleComponent) ap).getCursor();
3468                         } else {
3469                             return null;
3470                         }
3471                     }
3472                 }
3473             }
3474 
3475             public void setCursor(Cursor c) {
3476                 AccessibleContext ac = getCurrentAccessibleContext();
3477                 if (ac instanceof AccessibleComponent) {
3478                     ((AccessibleComponent) ac).setCursor(c);
3479                 } else {
3480                     Component cp = getCurrentComponent();
3481                     if (cp != null) {
3482                         cp.setCursor(c);
3483                     }
3484                 }
3485             }
3486 
3487             public Font getFont() {
3488                 AccessibleContext ac = getCurrentAccessibleContext();
3489                 if (ac instanceof AccessibleComponent) {
3490                     return ((AccessibleComponent) ac).getFont();
3491                 } else {
3492                     Component c = getCurrentComponent();
3493                     if (c != null) {
3494                         return c.getFont();
3495                     } else {
3496                         return null;
3497                     }
3498                 }
3499             }
3500 
3501             public void setFont(Font f) {
3502                 AccessibleContext ac = getCurrentAccessibleContext();
3503                 if (ac instanceof AccessibleComponent) {
3504                     ((AccessibleComponent) ac).setFont(f);
3505                 } else {
3506                     Component c = getCurrentComponent();
3507                     if (c != null) {
3508                         c.setFont(f);
3509                     }
3510                 }
3511             }
3512 
3513             public FontMetrics getFontMetrics(Font f) {
3514                 AccessibleContext ac = getCurrentAccessibleContext();
3515                 if (ac instanceof AccessibleComponent) {
3516                     return ((AccessibleComponent) ac).getFontMetrics(f);
3517                 } else {
3518                     Component c = getCurrentComponent();
3519                     if (c != null) {
3520                         return c.getFontMetrics(f);
3521                     } else {
3522                         return null;
3523                     }
3524                 }
3525             }
3526 
3527             public boolean isEnabled() {
3528                 AccessibleContext ac = getCurrentAccessibleContext();
3529                 if (ac instanceof AccessibleComponent) {
3530                     return ((AccessibleComponent) ac).isEnabled();
3531                 } else {
3532                     Component c = getCurrentComponent();
3533                     if (c != null) {
3534                         return c.isEnabled();
3535                     } else {
3536                         return false;
3537                     }
3538                 }
3539             }
3540 
3541             public void setEnabled(boolean b) {
3542                 AccessibleContext ac = getCurrentAccessibleContext();
3543                 if (ac instanceof AccessibleComponent) {
3544                     ((AccessibleComponent) ac).setEnabled(b);
3545                 } else {
3546                     Component c = getCurrentComponent();
3547                     if (c != null) {
3548                         c.setEnabled(b);
3549                     }
3550                 }
3551             }
3552 
3553             public boolean isVisible() {
3554                 int fi = parent.getFirstVisibleIndex();
3555                 int li = parent.getLastVisibleIndex();
3556                 // The UI incorrectly returns a -1 for the last
3557                 // visible index if the list is smaller than the
3558                 // viewport size.
3559                 if (li == -1) {
3560                     li = parent.getModel().getSize() - 1;
3561                 }
3562                 return ((indexInParent >= fi)
3563                         && (indexInParent <= li));
3564             }
3565 
3566             public void setVisible(boolean b) {
3567             }
3568 
3569             public boolean isShowing() {
3570                 return (parent.isShowing() && isVisible());
3571             }
3572 
3573             public boolean contains(Point p) {
3574                 AccessibleContext ac = getCurrentAccessibleContext();
3575                 if (ac instanceof AccessibleComponent) {
3576                     Rectangle r = ((AccessibleComponent) ac).getBounds();
3577                     return r.contains(p);
3578                 } else {
3579                     Component c = getCurrentComponent();
3580                     if (c != null) {
3581                         Rectangle r = c.getBounds();
3582                         return r.contains(p);
3583                     } else {
3584                         return getBounds().contains(p);
3585                     }
3586                 }
3587             }
3588 
3589             public Point getLocationOnScreen() {
3590                 if (parent != null) {
3591                     Point listLocation = parent.getLocationOnScreen();
3592                     Point componentLocation = parent.indexToLocation(indexInParent);
3593                     if (componentLocation != null) {
3594                         componentLocation.translate(listLocation.x, listLocation.y);
3595                         return componentLocation;
3596                     } else {
3597                         return null;
3598                     }
3599                 } else {
3600                     return null;
3601                 }
3602             }
3603 
3604             public Point getLocation() {
3605                 if (parent != null) {
3606                     return parent.indexToLocation(indexInParent);
3607                 } else {
3608                     return null;
3609                 }
3610             }
3611 
3612             public void setLocation(Point p) {
3613                 if ((parent != null)  && (parent.contains(p))) {
3614                     ensureIndexIsVisible(indexInParent);
3615                 }
3616             }
3617 
3618             public Rectangle getBounds() {
3619                 if (parent != null) {
3620                     return parent.getCellBounds(indexInParent,indexInParent);
3621                 } else {
3622                     return null;
3623                 }
3624             }
3625 
3626             public void setBounds(Rectangle r) {
3627                 AccessibleContext ac = getCurrentAccessibleContext();
3628                 if (ac instanceof AccessibleComponent) {
3629                     ((AccessibleComponent) ac).setBounds(r);
3630                 }
3631             }
3632 
3633             public Dimension getSize() {
3634                 Rectangle cellBounds = this.getBounds();
3635                 if (cellBounds != null) {
3636                     return cellBounds.getSize();
3637                 } else {
3638                     return null;
3639                 }
3640             }
3641 
3642             public void setSize (Dimension d) {
3643                 AccessibleContext ac = getCurrentAccessibleContext();
3644                 if (ac instanceof AccessibleComponent) {
3645                     ((AccessibleComponent) ac).setSize(d);
3646                 } else {
3647                     Component c = getCurrentComponent();
3648                     if (c != null) {
3649                         c.setSize(d);
3650                     }
3651                 }
3652             }
3653 
3654             public Accessible getAccessibleAt(Point p) {
3655                 AccessibleContext ac = getCurrentAccessibleContext();
3656                 if (ac instanceof AccessibleComponent) {
3657                     return ((AccessibleComponent) ac).getAccessibleAt(p);
3658                 } else {
3659                     return null;
3660                 }
3661             }
3662 
3663             public boolean isFocusTraversable() {
3664                 AccessibleContext ac = getCurrentAccessibleContext();
3665                 if (ac instanceof AccessibleComponent) {
3666                     return ((AccessibleComponent) ac).isFocusTraversable();
3667                 } else {
3668                     Component c = getCurrentComponent();
3669                     if (c != null) {
3670                         return c.isFocusTraversable();
3671                     } else {
3672                         return false;
3673                     }
3674                 }
3675             }
3676 
3677             public void requestFocus() {
3678                 AccessibleContext ac = getCurrentAccessibleContext();
3679                 if (ac instanceof AccessibleComponent) {
3680                     ((AccessibleComponent) ac).requestFocus();
3681                 } else {
3682                     Component c = getCurrentComponent();
3683                     if (c != null) {
3684                         c.requestFocus();
3685                     }
3686                 }
3687             }
3688 
3689             public void addFocusListener(FocusListener l) {
3690                 AccessibleContext ac = getCurrentAccessibleContext();
3691                 if (ac instanceof AccessibleComponent) {
3692                     ((AccessibleComponent) ac).addFocusListener(l);
3693                 } else {
3694                     Component c = getCurrentComponent();
3695                     if (c != null) {
3696                         c.addFocusListener(l);
3697                     }
3698                 }
3699             }
3700 
3701             public void removeFocusListener(FocusListener l) {
3702                 AccessibleContext ac = getCurrentAccessibleContext();
3703                 if (ac instanceof AccessibleComponent) {
3704                     ((AccessibleComponent) ac).removeFocusListener(l);
3705                 } else {
3706                     Component c = getCurrentComponent();
3707                     if (c != null) {
3708                         c.removeFocusListener(l);
3709                     }
3710                 }
3711             }
3712 
3713             // TIGER - 4733624
3714             /**
3715              * Returns the icon for the element renderer, as the only item
3716              * of an array of <code>AccessibleIcon</code>s or a <code>null</code> array
3717              * if the renderer component contains no icons.
3718              *
3719              * @return an array containing the accessible icon
3720              *         or a <code>null</code> array if none
3721              * @since 1.3
3722              */
3723             public AccessibleIcon [] getAccessibleIcon() {
3724                 AccessibleContext ac = getCurrentAccessibleContext();
3725                 if (ac != null) {
3726                     return ac.getAccessibleIcon();
3727                 } else {
3728                     return null;
3729                 }
3730             }
3731         } // inner class AccessibleJListChild
3732     } // inner class AccessibleJList
3733 }