001 /*
002 * Copyright (c) 2000 World Wide Web Consortium,
003 * (Massachusetts Institute of Technology, Institut National de
004 * Recherche en Informatique et en Automatique, Keio University). All
005 * Rights Reserved. This program is distributed under the W3C's Software
006 * Intellectual Property License. This program is distributed in the
007 * hope that it will be useful, but WITHOUT ANY WARRANTY; without even
008 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
009 * PURPOSE.
010 * See W3C License http://www.w3.org/Consortium/Legal/ for more details.
011 */
012
013 package org.w3c.dom.traversal;
014
015 import org.w3c.dom.Node;
016
017 /**
018 * Filters are objects that know how to "filter out" nodes. If a
019 * <code>NodeIterator</code> or <code>TreeWalker</code> is given a
020 * <code>NodeFilter</code>, it applies the filter before it returns the next
021 * node. If the filter says to accept the node, the traversal logic returns
022 * it; otherwise, traversal looks for the next node and pretends that the
023 * node that was rejected was not there.
024 * <p>The DOM does not provide any filters. <code>NodeFilter</code> is just an
025 * interface that users can implement to provide their own filters.
026 * <p><code>NodeFilters</code> do not need to know how to traverse from node
027 * to node, nor do they need to know anything about the data structure that
028 * is being traversed. This makes it very easy to write filters, since the
029 * only thing they have to know how to do is evaluate a single node. One
030 * filter may be used with a number of different kinds of traversals,
031 * encouraging code reuse.
032 * <p>See also the <a href='http://www.w3.org/TR/2000/REC-DOM-Level-2-Traversal-Range-20001113'>Document Object Model (DOM) Level 2 Traversal and Range Specification</a>.
033 * @since DOM Level 2
034 */
035 public interface NodeFilter {
036 // Constants returned by acceptNode
037 /**
038 * Accept the node. Navigation methods defined for
039 * <code>NodeIterator</code> or <code>TreeWalker</code> will return this
040 * node.
041 */
042 public static final short FILTER_ACCEPT = 1;
043 /**
044 * Reject the node. Navigation methods defined for
045 * <code>NodeIterator</code> or <code>TreeWalker</code> will not return
046 * this node. For <code>TreeWalker</code>, the children of this node
047 * will also be rejected. <code>NodeIterators</code> treat this as a
048 * synonym for <code>FILTER_SKIP</code>.
049 */
050 public static final short FILTER_REJECT = 2;
051 /**
052 * Skip this single node. Navigation methods defined for
053 * <code>NodeIterator</code> or <code>TreeWalker</code> will not return
054 * this node. For both <code>NodeIterator</code> and
055 * <code>TreeWalker</code>, the children of this node will still be
056 * considered.
057 */
058 public static final short FILTER_SKIP = 3;
059
060 // Constants for whatToShow
061 /**
062 * Show all <code>Nodes</code>.
063 */
064 public static final int SHOW_ALL = 0xFFFFFFFF;
065 /**
066 * Show <code>Element</code> nodes.
067 */
068 public static final int SHOW_ELEMENT = 0x00000001;
069 /**
070 * Show <code>Attr</code> nodes. This is meaningful only when creating an
071 * <code>NodeIterator</code> or <code>TreeWalker</code> with an
072 * attribute node as its <code>root</code>; in this case, it means that
073 * the attribute node will appear in the first position of the iteration
074 * or traversal. Since attributes are never children of other nodes,
075 * they do not appear when traversing over the document tree.
076 */
077 public static final int SHOW_ATTRIBUTE = 0x00000002;
078 /**
079 * Show <code>Text</code> nodes.
080 */
081 public static final int SHOW_TEXT = 0x00000004;
082 /**
083 * Show <code>CDATASection</code> nodes.
084 */
085 public static final int SHOW_CDATA_SECTION = 0x00000008;
086 /**
087 * Show <code>EntityReference</code> nodes.
088 */
089 public static final int SHOW_ENTITY_REFERENCE = 0x00000010;
090 /**
091 * Show <code>Entity</code> nodes. This is meaningful only when creating
092 * an <code>NodeIterator</code> or <code>TreeWalker</code> with an
093 * <code>Entity</code> node as its <code>root</code>; in this case, it
094 * means that the <code>Entity</code> node will appear in the first
095 * position of the traversal. Since entities are not part of the
096 * document tree, they do not appear when traversing over the document
097 * tree.
098 */
099 public static final int SHOW_ENTITY = 0x00000020;
100 /**
101 * Show <code>ProcessingInstruction</code> nodes.
102 */
103 public static final int SHOW_PROCESSING_INSTRUCTION = 0x00000040;
104 /**
105 * Show <code>Comment</code> nodes.
106 */
107 public static final int SHOW_COMMENT = 0x00000080;
108 /**
109 * Show <code>Document</code> nodes.
110 */
111 public static final int SHOW_DOCUMENT = 0x00000100;
112 /**
113 * Show <code>DocumentType</code> nodes.
114 */
115 public static final int SHOW_DOCUMENT_TYPE = 0x00000200;
116 /**
117 * Show <code>DocumentFragment</code> nodes.
118 */
119 public static final int SHOW_DOCUMENT_FRAGMENT = 0x00000400;
120 /**
121 * Show <code>Notation</code> nodes. This is meaningful only when creating
122 * an <code>NodeIterator</code> or <code>TreeWalker</code> with a
123 * <code>Notation</code> node as its <code>root</code>; in this case, it
124 * means that the <code>Notation</code> node will appear in the first
125 * position of the traversal. Since notations are not part of the
126 * document tree, they do not appear when traversing over the document
127 * tree.
128 */
129 public static final int SHOW_NOTATION = 0x00000800;
130
131 /**
132 * Test whether a specified node is visible in the logical view of a
133 * <code>TreeWalker</code> or <code>NodeIterator</code>. This function
134 * will be called by the implementation of <code>TreeWalker</code> and
135 * <code>NodeIterator</code>; it is not normally called directly from
136 * user code. (Though you could do so if you wanted to use the same
137 * filter to guide your own application logic.)
138 * @param n The node to check to see if it passes the filter or not.
139 * @return A constant to determine whether the node is accepted,
140 * rejected, or skipped, as defined above.
141 */
142 public short acceptNode(Node n);
143
144 }