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
13package org.w3c.dom.traversal;
14
15import org.w3c.dom.DOMException;
16import org.w3c.dom.Node;
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 * @hide
32 */
33public interface NodeIterator {
34    /**
35     * The root node of the <code>NodeIterator</code>, as specified when it
36     * was created.
37     */
38    public Node getRoot();
39
40    /**
41     * This attribute determines which node types are presented via the
42     * <code>NodeIterator</code>. The available set of constants is defined
43     * in the <code>NodeFilter</code> interface.  Nodes not accepted by
44     * <code>whatToShow</code> will be skipped, but their children may still
45     * be considered. Note that this skip takes precedence over the filter,
46     * if any.
47     */
48    public int getWhatToShow();
49
50    /**
51     * The <code>NodeFilter</code> used to screen nodes.
52     */
53    public NodeFilter getFilter();
54
55    /**
56     *  The value of this flag determines whether the children of entity
57     * reference nodes are visible to the <code>NodeIterator</code>. If
58     * false, these children  and their descendants will be rejected. Note
59     * that this rejection takes precedence over <code>whatToShow</code> and
60     * the filter. Also note that this is currently the only situation where
61     * <code>NodeIterators</code> may reject a complete subtree rather than
62     * skipping individual nodes.
63     * <br>
64     * <br> To produce a view of the document that has entity references
65     * expanded and does not expose the entity reference node itself, use
66     * the <code>whatToShow</code> flags to hide the entity reference node
67     * and set <code>expandEntityReferences</code> to true when creating the
68     * <code>NodeIterator</code>. To produce a view of the document that has
69     * entity reference nodes but no entity expansion, use the
70     * <code>whatToShow</code> flags to show the entity reference node and
71     * set <code>expandEntityReferences</code> to false.
72     */
73    public boolean getExpandEntityReferences();
74
75    /**
76     * Returns the next node in the set and advances the position of the
77     * <code>NodeIterator</code> in the set. After a
78     * <code>NodeIterator</code> is created, the first call to
79     * <code>nextNode()</code> returns the first node in the set.
80     * @return The next <code>Node</code> in the set being iterated over, or
81     *   <code>null</code> if there are no more members in that set.
82     * @exception DOMException
83     *   INVALID_STATE_ERR: Raised if this method is called after the
84     *   <code>detach</code> method was invoked.
85     */
86    public Node nextNode()
87                         throws DOMException;
88
89    /**
90     * Returns the previous node in the set and moves the position of the
91     * <code>NodeIterator</code> backwards in the set.
92     * @return The previous <code>Node</code> in the set being iterated over,
93     *   or <code>null</code> if there are no more members in that set.
94     * @exception DOMException
95     *   INVALID_STATE_ERR: Raised if this method is called after the
96     *   <code>detach</code> method was invoked.
97     */
98    public Node previousNode()
99                             throws DOMException;
100
101    /**
102     * Detaches the <code>NodeIterator</code> from the set which it iterated
103     * over, releasing any computational resources and placing the
104     * <code>NodeIterator</code> in the INVALID state. After
105     * <code>detach</code> has been invoked, calls to <code>nextNode</code>
106     * or <code>previousNode</code> will raise the exception
107     * INVALID_STATE_ERR.
108     */
109    public void detach();
110
111}
112