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Java > Open Source Codes > org > w3c > dom > traversal > NodeIterator


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 JavaDoc;
16 import org.w3c.dom.DOMException JavaDoc;
17
18 /**
19  * <code>NodeIterators</code> are used to step through a set of nodes, e.g.
20  * the set of nodes in a <code>NodeList</code>, the document subtree
21  * governed by a particular <code>Node</code>, the results of a query, or
22  * any other set of nodes. The set of nodes to be iterated is determined by
23  * the implementation of the <code>NodeIterator</code>. DOM Level 2
24  * specifies a single <code>NodeIterator</code> implementation for
25  * document-order traversal of a document subtree. Instances of these
26  * <code>NodeIterators</code> are created by calling
27  * <code>DocumentTraversal</code><code>.createNodeIterator()</code>.
28  * <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>.
29  * @since DOM Level 2
30  */
31 public interface NodeIterator {
32     /**
33      * The root node of the <code>NodeIterator</code>, as specified when it
34      * was created.
35      */
36     public Node JavaDoc getRoot();
37
38     /**
39      * This attribute determines which node types are presented via the
40      * <code>NodeIterator</code>. The available set of constants is defined
41      * in the <code>NodeFilter</code> interface. Nodes not accepted by
42      * <code>whatToShow</code> will be skipped, but their children may still
43      * be considered. Note that this skip takes precedence over the filter,
44      * if any.
45      */
46     public int getWhatToShow();
47
48     /**
49      * The <code>NodeFilter</code> used to screen nodes.
50      */
51     public NodeFilter getFilter();
52
53     /**
54      * The value of this flag determines whether the children of entity
55      * reference nodes are visible to the <code>NodeIterator</code>. If
56      * false, these children and their descendants will be rejected. Note
57      * that this rejection takes precedence over <code>whatToShow</code> and
58      * the filter. Also note that this is currently the only situation where
59      * <code>NodeIterators</code> may reject a complete subtree rather than
60      * skipping individual nodes.
61      * <br>
62      * <br> To produce a view of the document that has entity references
63      * expanded and does not expose the entity reference node itself, use
64      * the <code>whatToShow</code> flags to hide the entity reference node
65      * and set <code>expandEntityReferences</code> to true when creating the
66      * <code>NodeIterator</code>. To produce a view of the document that has
67      * entity reference nodes but no entity expansion, use the
68      * <code>whatToShow</code> flags to show the entity reference node and
69      * set <code>expandEntityReferences</code> to false.
70      */
71     public boolean getExpandEntityReferences();
72
73     /**
74      * Returns the next node in the set and advances the position of the
75      * <code>NodeIterator</code> in the set. After a
76      * <code>NodeIterator</code> is created, the first call to
77      * <code>nextNode()</code> returns the first node in the set.
78      * @return The next <code>Node</code> in the set being iterated over, or
79      * <code>null</code> if there are no more members in that set.
80      * @exception DOMException
81      * INVALID_STATE_ERR: Raised if this method is called after the
82      * <code>detach</code> method was invoked.
83      */
84     public Node JavaDoc nextNode()
85                          throws DOMException JavaDoc;
86
87     /**
88      * Returns the previous node in the set and moves the position of the
89      * <code>NodeIterator</code> backwards in the set.
90      * @return The previous <code>Node</code> in the set being iterated over,
91      * or <code>null</code> if there are no more members in that set.
92      * @exception DOMException
93      * INVALID_STATE_ERR: Raised if this method is called after the
94      * <code>detach</code> method was invoked.
95      */
96     public Node JavaDoc previousNode()
97                              throws DOMException JavaDoc;
98
99     /**
100      * Detaches the <code>NodeIterator</code> from the set which it iterated
101      * over, releasing any computational resources and placing the
102      * <code>NodeIterator</code> in the INVALID state. After
103      * <code>detach</code> has been invoked, calls to <code>nextNode</code>
104      * or <code>previousNode</code> will raise the exception
105      * INVALID_STATE_ERR.
106      */
107     public void detach();
108
109 }
110
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