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 import org.w3c.dom.DOMException;
17
18 /**
19 * <code>TreeWalker</code> objects are used to navigate a document tree or
20 * subtree using the view of the document defined by their
21 * <code>whatToShow</code> flags and filter (if any). Any function which
22 * performs navigation using a <code>TreeWalker</code> will automatically
23 * support any view defined by a <code>TreeWalker</code>.
24 * <p>Omitting nodes from the logical view of a subtree can result in a
25 * structure that is substantially different from the same subtree in the
26 * complete, unfiltered document. Nodes that are siblings in the
27 * <code>TreeWalker</code> view may be children of different, widely
28 * separated nodes in the original view. For instance, consider a
29 * <code>NodeFilter</code> that skips all nodes except for Text nodes and
30 * the root node of a document. In the logical view that results, all text
31 * nodes will be siblings and appear as direct children of the root node, no
32 * matter how deeply nested the structure of the original document.
33 * <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>.
34 * @since DOM Level 2
35 */
36 public interface TreeWalker {
37 /**
38 * The <code>root</code> node of the <code>TreeWalker</code>, as specified
39 * when it was created.
40 */
41 public Node getRoot();
42
43 /**
44 * This attribute determines which node types are presented via the
45 * <code>TreeWalker</code>. The available set of constants is defined in
46 * the <code>NodeFilter</code> interface. Nodes not accepted by
47 * <code>whatToShow</code> will be skipped, but their children may still
48 * be considered. Note that this skip takes precedence over the filter,
49 * if any.
50 */
51 public int getWhatToShow();
52
53 /**
54 * The filter used to screen nodes.
55 */
56 public NodeFilter getFilter();
57
58 /**
59 * The value of this flag determines whether the children of entity
60 * reference nodes are visible to the <code>TreeWalker</code>. If false,
61 * these children and their descendants will be rejected. Note that
62 * this rejection takes precedence over <code>whatToShow</code> and the
63 * filter, if any.
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>TreeWalker</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 * The node at which the <code>TreeWalker</code> is currently positioned.
77 * <br>Alterations to the DOM tree may cause the current node to no longer
78 * be accepted by the <code>TreeWalker</code>'s associated filter.
79 * <code>currentNode</code> may also be explicitly set to any node,
80 * whether or not it is within the subtree specified by the
81 * <code>root</code> node or would be accepted by the filter and
82 * <code>whatToShow</code> flags. Further traversal occurs relative to
83 * <code>currentNode</code> even if it is not part of the current view,
84 * by applying the filters in the requested direction; if no traversal
85 * is possible, <code>currentNode</code> is not changed.
86 */
87 public Node getCurrentNode();
88 /**
89 * The node at which the <code>TreeWalker</code> is currently positioned.
90 * <br>Alterations to the DOM tree may cause the current node to no longer
91 * be accepted by the <code>TreeWalker</code>'s associated filter.
92 * <code>currentNode</code> may also be explicitly set to any node,
93 * whether or not it is within the subtree specified by the
94 * <code>root</code> node or would be accepted by the filter and
95 * <code>whatToShow</code> flags. Further traversal occurs relative to
96 * <code>currentNode</code> even if it is not part of the current view,
97 * by applying the filters in the requested direction; if no traversal
98 * is possible, <code>currentNode</code> is not changed.
99 * @exception DOMException
100 * NOT_SUPPORTED_ERR: Raised if an attempt is made to set
101 * <code>currentNode</code> to <code>null</code>.
102 */
103 public void setCurrentNode(Node currentNode)
104 throws DOMException;
105
106 /**
107 * Moves to and returns the closest visible ancestor node of the current
108 * node. If the search for <code>parentNode</code> attempts to step
109 * upward from the <code>TreeWalker</code>'s <code>root</code> node, or
110 * if it fails to find a visible ancestor node, this method retains the
111 * current position and returns <code>null</code>.
112 * @return The new parent node, or <code>null</code> if the current node
113 * has no parent in the <code>TreeWalker</code>'s logical view.
114 */
115 public Node parentNode();
116
117 /**
118 * Moves the <code>TreeWalker</code> to the first visible child of the
119 * current node, and returns the new node. If the current node has no
120 * visible children, returns <code>null</code>, and retains the current
121 * node.
122 * @return The new node, or <code>null</code> if the current node has no
123 * visible children in the <code>TreeWalker</code>'s logical view.
124 */
125 public Node firstChild();
126
127 /**
128 * Moves the <code>TreeWalker</code> to the last visible child of the
129 * current node, and returns the new node. If the current node has no
130 * visible children, returns <code>null</code>, and retains the current
131 * node.
132 * @return The new node, or <code>null</code> if the current node has no
133 * children in the <code>TreeWalker</code>'s logical view.
134 */
135 public Node lastChild();
136
137 /**
138 * Moves the <code>TreeWalker</code> to the previous sibling of the
139 * current node, and returns the new node. If the current node has no
140 * visible previous sibling, returns <code>null</code>, and retains the
141 * current node.
142 * @return The new node, or <code>null</code> if the current node has no
143 * previous sibling. in the <code>TreeWalker</code>'s logical view.
144 */
145 public Node previousSibling();
146
147 /**
148 * Moves the <code>TreeWalker</code> to the next sibling of the current
149 * node, and returns the new node. If the current node has no visible
150 * next sibling, returns <code>null</code>, and retains the current node.
151 * @return The new node, or <code>null</code> if the current node has no
152 * next sibling. in the <code>TreeWalker</code>'s logical view.
153 */
154 public Node nextSibling();
155
156 /**
157 * Moves the <code>TreeWalker</code> to the previous visible node in
158 * document order relative to the current node, and returns the new
159 * node. If the current node has no previous node, or if the search for
160 * <code>previousNode</code> attempts to step upward from the
161 * <code>TreeWalker</code>'s <code>root</code> node, returns
162 * <code>null</code>, and retains the current node.
163 * @return The new node, or <code>null</code> if the current node has no
164 * previous node in the <code>TreeWalker</code>'s logical view.
165 */
166 public Node previousNode();
167
168 /**
169 * Moves the <code>TreeWalker</code> to the next visible node in document
170 * order relative to the current node, and returns the new node. If the
171 * current node has no next node, or if the search for nextNode attempts
172 * to step upward from the <code>TreeWalker</code>'s <code>root</code>
173 * node, returns <code>null</code>, and retains the current node.
174 * @return The new node, or <code>null</code> if the current node has no
175 * next node in the <code>TreeWalker</code>'s logical view.
176 */
177 public Node nextNode();
178
179 }