1 /*
2  * Copyright (c) 2000 World Wide Web Consortium,
3  * (Massachusetts Institute of Technology, Institut National de
4  * Recherche en Informatique et en Automatique, Keio University). All
5  * Rights Reserved. This program is distributed under the W3C's Software
6  * Intellectual Property License. This program is distributed in the
7  * hope that it will be useful, but WITHOUT ANY WARRANTY; without even
8  * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
9  * PURPOSE.
10  * See W3C License http://www.w3.org/Consortium/Legal/ for more details.
11  */
12 
13 package org.w3c.dom.traversal;
14 
15 import org.w3c.dom.Node;
16 
17 /**
18  * Filters are objects that know how to "filter out" nodes. If a
19  * <code>NodeIterator</code> or <code>TreeWalker</code> is given a
20  * <code>NodeFilter</code>, it applies the filter before it returns the next
21  * node. If the filter says to accept the node, the traversal logic returns
22  * it; otherwise, traversal looks for the next node and pretends that the
23  * node that was rejected was not there.
24  * <p>The DOM does not provide any filters. <code>NodeFilter</code> is just an
25  * interface that users can implement to provide their own filters.
26  * <p><code>NodeFilters</code> do not need to know how to traverse from node
27  * to node, nor do they need to know anything about the data structure that
28  * is being traversed. This makes it very easy to write filters, since the
29  * only thing they have to know how to do is evaluate a single node. One
30  * filter may be used with a number of different kinds of traversals,
31  * encouraging code reuse.
32  * <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>.
33  * @since DOM Level 2
34  *
35  * @hide
36  */
37 public interface NodeFilter {
38     // Constants returned by acceptNode
39     /**
40      * Accept the node. Navigation methods defined for
41      * <code>NodeIterator</code> or <code>TreeWalker</code> will return this
42      * node.
43      */
44     public static final short FILTER_ACCEPT             = 1;
45     /**
46      * Reject the node. Navigation methods defined for
47      * <code>NodeIterator</code> or <code>TreeWalker</code> will not return
48      * this node. For <code>TreeWalker</code>, the children of this node
49      * will also be rejected. <code>NodeIterators</code> treat this as a
50      * synonym for <code>FILTER_SKIP</code>.
51      */
52     public static final short FILTER_REJECT             = 2;
53     /**
54      * Skip this single node. Navigation methods defined for
55      * <code>NodeIterator</code> or <code>TreeWalker</code> will not return
56      * this node. For both <code>NodeIterator</code> and
57      * <code>TreeWalker</code>, the children of this node will still be
58      * considered.
59      */
60     public static final short FILTER_SKIP               = 3;
61 
62     // Constants for whatToShow
63     /**
64      * Show all <code>Nodes</code>.
65      */
66     public static final int SHOW_ALL                  = 0xFFFFFFFF;
67     /**
68      * Show <code>Element</code> nodes.
69      */
70     public static final int SHOW_ELEMENT              = 0x00000001;
71     /**
72      * Show <code>Attr</code> nodes. This is meaningful only when creating an
73      * <code>NodeIterator</code> or <code>TreeWalker</code> with an
74      * attribute node as its <code>root</code>; in this case, it means that
75      * the attribute node will appear in the first position of the iteration
76      * or traversal. Since attributes are never children of other nodes,
77      * they do not appear when traversing over the document tree.
78      */
79     public static final int SHOW_ATTRIBUTE            = 0x00000002;
80     /**
81      * Show <code>Text</code> nodes.
82      */
83     public static final int SHOW_TEXT                 = 0x00000004;
84     /**
85      * Show <code>CDATASection</code> nodes.
86      */
87     public static final int SHOW_CDATA_SECTION        = 0x00000008;
88     /**
89      * Show <code>EntityReference</code> nodes.
90      */
91     public static final int SHOW_ENTITY_REFERENCE     = 0x00000010;
92     /**
93      * Show <code>Entity</code> nodes. This is meaningful only when creating
94      * an <code>NodeIterator</code> or <code>TreeWalker</code> with an
95      * <code>Entity</code> node as its <code>root</code>; in this case, it
96      * means that the <code>Entity</code> node will appear in the first
97      * position of the traversal. Since entities are not part of the
98      * document tree, they do not appear when traversing over the document
99      * tree.
100      */
101     public static final int SHOW_ENTITY               = 0x00000020;
102     /**
103      * Show <code>ProcessingInstruction</code> nodes.
104      */
105     public static final int SHOW_PROCESSING_INSTRUCTION = 0x00000040;
106     /**
107      * Show <code>Comment</code> nodes.
108      */
109     public static final int SHOW_COMMENT              = 0x00000080;
110     /**
111      * Show <code>Document</code> nodes.
112      */
113     public static final int SHOW_DOCUMENT             = 0x00000100;
114     /**
115      * Show <code>DocumentType</code> nodes.
116      */
117     public static final int SHOW_DOCUMENT_TYPE        = 0x00000200;
118     /**
119      * Show <code>DocumentFragment</code> nodes.
120      */
121     public static final int SHOW_DOCUMENT_FRAGMENT    = 0x00000400;
122     /**
123      * Show <code>Notation</code> nodes. This is meaningful only when creating
124      * an <code>NodeIterator</code> or <code>TreeWalker</code> with a
125      * <code>Notation</code> node as its <code>root</code>; in this case, it
126      * means that the <code>Notation</code> node will appear in the first
127      * position of the traversal. Since notations are not part of the
128      * document tree, they do not appear when traversing over the document
129      * tree.
130      */
131     public static final int SHOW_NOTATION             = 0x00000800;
132 
133     /**
134      * Test whether a specified node is visible in the logical view of a
135      * <code>TreeWalker</code> or <code>NodeIterator</code>. This function
136      * will be called by the implementation of <code>TreeWalker</code> and
137      * <code>NodeIterator</code>; it is not normally called directly from
138      * user code. (Though you could do so if you wanted to use the same
139      * filter to guide your own application logic.)
140      * @param n The node to check to see if it passes the filter or not.
141      * @return A constant to determine whether the node is accepted,
142      *   rejected, or skipped, as defined above.
143      */
acceptNode(Node n)144     public short acceptNode(Node n);
145 
146 }
147