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1   /*
2    * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
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7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
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25  
26  
27  package javax.management.openmbean;
28  
29  
30  // java import
31  //
32  import java.util.ArrayList;
33  import java.util.Collections;
34  import java.util.Iterator;
35  import java.util.List;
36  
37  // jmx import
38  //
39  
40  
41  /**
42   * The <code>TabularType</code> class is the <i> open type</i> class
43   * whose instances describe the types of {@link TabularData TabularData} values.
44   *
45   * @since 1.5
46   */
47  public class TabularType extends OpenType<TabularData> {
48  
49      /* Serial version */
50      static final long serialVersionUID = 6554071860220659261L;
51  
52  
53      /**
54       * @serial The composite type of rows
55       */
56      private CompositeType  rowType;
57  
58      /**
59       * @serial The items used to index each row element, kept in the order the user gave
60       *         This is an unmodifiable {@link ArrayList}
61       */
62      private List<String> indexNames;
63  
64  
65      private transient Integer myHashCode = null; // As this instance is immutable, these two values
66      private transient String  myToString = null; // need only be calculated once.
67  
68  
69      /* *** Constructor *** */
70  
71      /**
72       * Constructs a <code>TabularType</code> instance, checking for the validity of the given parameters.
73       * The validity constraints are described below for each parameter.
74       * <p>
75       * The Java class name of tabular data values this tabular type represents
76       * (ie the class name returned by the {@link OpenType#getClassName() getClassName} method)
77       * is set to the string value returned by <code>TabularData.class.getName()</code>.
78       * <p>
79       * @param  typeName  The name given to the tabular type this instance represents; cannot be a null or empty string.
80       * <br>&nbsp;
81       * @param  description  The human readable description of the tabular type this instance represents;
82       *                      cannot be a null or empty string.
83       * <br>&nbsp;
84       * @param  rowType  The type of the row elements of tabular data values described by this tabular type instance;
85       *                  cannot be null.
86       * <br>&nbsp;
87       * @param  indexNames  The names of the items the values of which are used to uniquely index each row element in the
88       *                     tabular data values described by this tabular type instance;
89       *                     cannot be null or empty. Each element should be an item name defined in <var>rowType</var>
90       *                     (no null or empty string allowed).
91       *                     It is important to note that the <b>order</b> of the item names in <var>indexNames</var>
92       *                     is used by the methods {@link TabularData#get(java.lang.Object[]) get} and
93       *                     {@link TabularData#remove(java.lang.Object[]) remove} of class
94       *                     <code>TabularData</code> to match their array of values parameter to items.
95       * <br>&nbsp;
96       * @throws IllegalArgumentException  if <var>rowType</var> is null,
97       *                                   or <var>indexNames</var> is a null or empty array,
98       *                                   or an element in <var>indexNames</var> is a null or empty string,
99       *                                   or <var>typeName</var> or <var>description</var> is a null or empty string.
100      * <br>&nbsp;
101      * @throws OpenDataException  if an element's value of <var>indexNames</var>
102      *                            is not an item name defined in <var>rowType</var>.
103      */
104     public TabularType(String         typeName,
105                        String         description,
106                        CompositeType  rowType,
107                        String[]       indexNames) throws OpenDataException {
108 
109         // Check and initialize state defined by parent.
110         //
111         super(TabularData.class.getName(), typeName, description, false);
112 
113         // Check rowType is not null
114         //
115         if (rowType == null) {
116             throw new IllegalArgumentException("Argument rowType cannot be null.");
117         }
118 
119         // Check indexNames is neither null nor empty and does not contain any null element or empty string
120         //
121         checkForNullElement(indexNames, "indexNames");
122         checkForEmptyString(indexNames, "indexNames");
123 
124         // Check all indexNames values are valid item names for rowType
125         //
126         for (int i=0; i<indexNames.length; i++) {
127             if ( ! rowType.containsKey(indexNames[i]) ) {
128                 throw new OpenDataException("Argument's element value indexNames["+ i +"]=\""+ indexNames[i] +
129                                             "\" is not a valid item name for rowType.");
130             }
131         }
132 
133         // initialize rowType
134         //
135         this.rowType    = rowType;
136 
137         // initialize indexNames (copy content so that subsequent
138         // modifs to the array referenced by the indexNames parameter
139         // have no impact)
140         //
141         List<String> tmpList = new ArrayList<String>(indexNames.length + 1);
142         for (int i=0; i<indexNames.length; i++) {
143             tmpList.add(indexNames[i]);
144         }
145         this.indexNames = Collections.unmodifiableList(tmpList);
146     }
147 
148     /**
149      * Checks that Object[] arg is neither null nor empty (ie length==0)
150      * and that it does not contain any null element.
151      */
152     private static void checkForNullElement(Object[] arg, String argName) {
153         if ( (arg == null) || (arg.length == 0) ) {
154             throw new IllegalArgumentException("Argument "+ argName +"[] cannot be null or empty.");
155         }
156         for (int i=0; i<arg.length; i++) {
157             if (arg[i] == null) {
158                 throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be null.");
159             }
160         }
161     }
162 
163     /**
164      * Checks that String[] does not contain any empty (or blank characters only) string.
165      */
166     private static void checkForEmptyString(String[] arg, String argName) {
167         for (int i=0; i<arg.length; i++) {
168             if (arg[i].trim().equals("")) {
169                 throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be an empty string.");
170             }
171         }
172     }
173 
174 
175     /* *** Tabular type specific information methods *** */
176 
177     /**
178      * Returns the type of the row elements of tabular data values
179      * described by this <code>TabularType</code> instance.
180      *
181      * @return the type of each row.
182      */
183     public CompositeType getRowType() {
184 
185         return rowType;
186     }
187 
188     /**
189      * <p>Returns, in the same order as was given to this instance's
190      * constructor, an unmodifiable List of the names of the items the
191      * values of which are used to uniquely index each row element of
192      * tabular data values described by this <code>TabularType</code>
193      * instance.</p>
194      *
195      * @return a List of String representing the names of the index
196      * items.
197      *
198      */
199     public List<String> getIndexNames() {
200 
201         return indexNames;
202     }
203 
204     /**
205      * Tests whether <var>obj</var> is a value which could be
206      * described by this <code>TabularType</code> instance.
207      *
208      * <p>If <var>obj</var> is null or is not an instance of
209      * <code>javax.management.openmbean.TabularData</code>,
210      * <code>isValue</code> returns <code>false</code>.</p>
211      *
212      * <p>If <var>obj</var> is an instance of
213      * <code>javax.management.openmbean.TabularData</code>, say {@code
214      * td}, the result is true if this {@code TabularType} is
215      * <em>assignable from</em> {@link TabularData#getTabularType()
216      * td.getTabularType()}, as defined in {@link
217      * CompositeType#isValue CompositeType.isValue}.</p>
218      *
219      * @param obj the value whose open type is to be tested for
220      * compatibility with this <code>TabularType</code> instance.
221      *
222      * @return <code>true</code> if <var>obj</var> is a value for this
223      * tabular type, <code>false</code> otherwise.
224      */
225     public boolean isValue(Object obj) {
226 
227         // if obj is null or not a TabularData, return false
228         //
229         if (!(obj instanceof TabularData))
230             return false;
231 
232         // if obj is not a TabularData, return false
233         //
234         TabularData value = (TabularData) obj;
235         TabularType valueType = value.getTabularType();
236         return isAssignableFrom(valueType);
237     }
238 
239     @Override
240     boolean isAssignableFrom(OpenType<?> ot) {
241         if (!(ot instanceof TabularType))
242             return false;
243         TabularType tt = (TabularType) ot;
244         if (!getTypeName().equals(tt.getTypeName()) ||
245                 !getIndexNames().equals(tt.getIndexNames()))
246             return false;
247         return getRowType().isAssignableFrom(tt.getRowType());
248     }
249 
250 
251     /* *** Methods overriden from class Object *** */
252 
253     /**
254      * Compares the specified <code>obj</code> parameter with this <code>TabularType</code> instance for equality.
255      * <p>
256      * Two <code>TabularType</code> instances are equal if and only if all of the following statements are true:
257      * <ul>
258      * <li>their type names are equal</li>
259      * <li>their row types are equal</li>
260      * <li>they use the same index names, in the same order</li>
261      * </ul>
262      * <br>&nbsp;
263      * @param  obj  the object to be compared for equality with this <code>TabularType</code> instance;
264      *              if <var>obj</var> is <code>null</code>, <code>equals</code> returns <code>false</code>.
265      *
266      * @return  <code>true</code> if the specified object is equal to this <code>TabularType</code> instance.
267      */
268     public boolean equals(Object obj) {
269 
270         // if obj is null, return false
271         //
272         if (obj == null) {
273             return false;
274         }
275 
276         // if obj is not a TabularType, return false
277         //
278         TabularType other;
279         try {
280             other = (TabularType) obj;
281         } catch (ClassCastException e) {
282             return false;
283         }
284 
285         // Now, really test for equality between this TabularType instance and the other:
286         //
287 
288         // their names should be equal
289         if ( ! this.getTypeName().equals(other.getTypeName()) ) {
290             return false;
291         }
292 
293         // their row types should be equal
294         if ( ! this.rowType.equals(other.rowType) ) {
295             return false;
296         }
297 
298         // their index names should be equal and in the same order (ensured by List.equals())
299         if ( ! this.indexNames.equals(other.indexNames) ) {
300             return false;
301         }
302 
303         // All tests for equality were successfull
304         //
305         return true;
306     }
307 
308     /**
309      * Returns the hash code value for this <code>TabularType</code> instance.
310      * <p>
311      * The hash code of a <code>TabularType</code> instance is the sum of the hash codes
312      * of all elements of information used in <code>equals</code> comparisons
313      * (ie: name, row type, index names).
314      * This ensures that <code> t1.equals(t2) </code> implies that <code> t1.hashCode()==t2.hashCode() </code>
315      * for any two <code>TabularType</code> instances <code>t1</code> and <code>t2</code>,
316      * as required by the general contract of the method
317      * {@link Object#hashCode() Object.hashCode()}.
318      * <p>
319      * As <code>TabularType</code> instances are immutable, the hash code for this instance is calculated once,
320      * on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.
321      *
322      * @return  the hash code value for this <code>TabularType</code> instance
323      */
324     public int hashCode() {
325 
326         // Calculate the hash code value if it has not yet been done (ie 1st call to hashCode())
327         //
328         if (myHashCode == null) {
329             int value = 0;
330             value += this.getTypeName().hashCode();
331             value += this.rowType.hashCode();
332             for (String index : indexNames)
333                 value += index.hashCode();
334             myHashCode = Integer.valueOf(value);
335         }
336 
337         // return always the same hash code for this instance (immutable)
338         //
339         return myHashCode.intValue();
340     }
341 
342     /**
343      * Returns a string representation of this <code>TabularType</code> instance.
344      * <p>
345      * The string representation consists of the name of this class (ie <code>javax.management.openmbean.TabularType</code>),
346      * the type name for this instance, the row type string representation of this instance,
347      * and the index names of this instance.
348      * <p>
349      * As <code>TabularType</code> instances are immutable, the string representation for this instance is calculated once,
350      * on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.
351      *
352      * @return  a string representation of this <code>TabularType</code> instance
353      */
354     public String toString() {
355 
356         // Calculate the string representation if it has not yet been done (ie 1st call to toString())
357         //
358         if (myToString == null) {
359             final StringBuilder result = new StringBuilder()
360                 .append(this.getClass().getName())
361                 .append("(name=")
362                 .append(getTypeName())
363                 .append(",rowType=")
364                 .append(rowType.toString())
365                 .append(",indexNames=(");
366             String sep = "";
367             for (String index : indexNames) {
368                 result.append(sep).append(index);
369                 sep = ",";
370             }
371             result.append("))");
372             myToString = result.toString();
373         }
374 
375         // return always the same string representation for this instance (immutable)
376         //
377         return myToString;
378     }
379 
380 }