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 */
25package 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 */
33public 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}
140