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1   /*
2    * Copyright (c) 1997, 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
6    * under the terms of the GNU General Public License version 2 only, as
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
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22   * or visit www.oracle.com if you need additional information or have any
23   * questions.
24   */
25  package javax.swing.text;
26  
27  /**
28   * Interface to describe a structural piece of a document.  It
29   * is intended to capture the spirit of an SGML element.
30   *
31   * @author  Timothy Prinzing
32   */
33  public interface Element {
34  
35      /**
36       * Fetches the document associated with this element.
37       *
38       * @return the document
39       */
40      public Document getDocument();
41  
42      /**
43       * Fetches the parent element.  If the element is a root level
44       * element returns <code>null</code>.
45       *
46       * @return the parent element
47       */
48      public Element getParentElement();
49  
50      /**
51       * Fetches the name of the element.  If the element is used to
52       * represent some type of structure, this would be the type
53       * name.
54       *
55       * @return the element name
56       */
57      public String getName();
58  
59      /**
60       * Fetches the collection of attributes this element contains.
61       *
62       * @return the attributes for the element
63       */
64      public AttributeSet getAttributes();
65  
66      /**
67       * Fetches the offset from the beginning of the document
68       * that this element begins at.  If this element has
69       * children, this will be the offset of the first child.
70       * As a document position, there is an implied forward bias.
71       *
72       * @return the starting offset &gt;= 0 and &lt; getEndOffset();
73       * @see Document
74       * @see AbstractDocument
75       */
76      public int getStartOffset();
77  
78      /**
79       * Fetches the offset from the beginning of the document
80       * that this element ends at.  If this element has
81       * children, this will be the end offset of the last child.
82       * As a document position, there is an implied backward bias.
83       * <p>
84       * All the default <code>Document</code> implementations
85       * descend from <code>AbstractDocument</code>.
86       * <code>AbstractDocument</code> models an implied break at the end of
87       * the document. As a result of this, it is possible for this to
88       * return a value greater than the length of the document.
89       *
90       * @return the ending offset &gt; getStartOffset() and
91       *     &lt;= getDocument().getLength() + 1
92       * @see Document
93       * @see AbstractDocument
94       */
95      public int getEndOffset();
96  
97      /**
98       * Gets the child element index closest to the given offset.
99       * The offset is specified relative to the beginning of the
100      * document.  Returns <code>-1</code> if the
101      * <code>Element</code> is a leaf, otherwise returns
102      * the index of the <code>Element</code> that best represents
103      * the given location.  Returns <code>0</code> if the location
104      * is less than the start offset. Returns
105      * <code>getElementCount() - 1</code> if the location is
106      * greater than or equal to the end offset.
107      *
108      * @param offset the specified offset &gt;= 0
109      * @return the element index &gt;= 0
110      */
111     public int getElementIndex(int offset);
112 
113     /**
114      * Gets the number of child elements contained by this element.
115      * If this element is a leaf, a count of zero is returned.
116      *
117      * @return the number of child elements &gt;= 0
118      */
119     public int getElementCount();
120 
121     /**
122      * Fetches the child element at the given index.
123      *
124      * @param index the specified index &gt;= 0
125      * @return the child element
126      */
127     public Element getElement(int index);
128 
129     /**
130      * Is this element a leaf element? An element that
131      * <i>may</i> have children, even if it currently
132      * has no children, would return <code>false</code>.
133      *
134      * @return true if a leaf element else false
135      */
136     public boolean isLeaf();
137 
138 
139 }