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 import org.w3c.dom.DOMException;
017
018 /**
019 * <code>TreeWalker</code> objects are used to navigate a document tree or
020 * subtree using the view of the document defined by their
021 * <code>whatToShow</code> flags and filter (if any). Any function which
022 * performs navigation using a <code>TreeWalker</code> will automatically
023 * support any view defined by a <code>TreeWalker</code>.
024 * <p>Omitting nodes from the logical view of a subtree can result in a
025 * structure that is substantially different from the same subtree in the
026 * complete, unfiltered document. Nodes that are siblings in the
027 * <code>TreeWalker</code> view may be children of different, widely
028 * separated nodes in the original view. For instance, consider a
029 * <code>NodeFilter</code> that skips all nodes except for Text nodes and
030 * the root node of a document. In the logical view that results, all text
031 * nodes will be siblings and appear as direct children of the root node, no
032 * matter how deeply nested the structure of the original document.
033 * <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>.
034 * @since DOM Level 2
035 */
036 public interface TreeWalker {
037 /**
038 * The <code>root</code> node of the <code>TreeWalker</code>, as specified
039 * when it was created.
040 */
041 public Node getRoot();
042
043 /**
044 * This attribute determines which node types are presented via the
045 * <code>TreeWalker</code>. The available set of constants is defined in
046 * the <code>NodeFilter</code> interface. Nodes not accepted by
047 * <code>whatToShow</code> will be skipped, but their children may still
048 * be considered. Note that this skip takes precedence over the filter,
049 * if any.
050 */
051 public int getWhatToShow();
052
053 /**
054 * The filter used to screen nodes.
055 */
056 public NodeFilter getFilter();
057
058 /**
059 * The value of this flag determines whether the children of entity
060 * reference nodes are visible to the <code>TreeWalker</code>. If false,
061 * these children and their descendants will be rejected. Note that
062 * this rejection takes precedence over <code>whatToShow</code> and the
063 * filter, if any.
064 * <br> To produce a view of the document that has entity references
065 * expanded and does not expose the entity reference node itself, use
066 * the <code>whatToShow</code> flags to hide the entity reference node
067 * and set <code>expandEntityReferences</code> to true when creating the
068 * <code>TreeWalker</code>. To produce a view of the document that has
069 * entity reference nodes but no entity expansion, use the
070 * <code>whatToShow</code> flags to show the entity reference node and
071 * set <code>expandEntityReferences</code> to false.
072 */
073 public boolean getExpandEntityReferences();
074
075 /**
076 * The node at which the <code>TreeWalker</code> is currently positioned.
077 * <br>Alterations to the DOM tree may cause the current node to no longer
078 * be accepted by the <code>TreeWalker</code>'s associated filter.
079 * <code>currentNode</code> may also be explicitly set to any node,
080 * whether or not it is within the subtree specified by the
081 * <code>root</code> node or would be accepted by the filter and
082 * <code>whatToShow</code> flags. Further traversal occurs relative to
083 * <code>currentNode</code> even if it is not part of the current view,
084 * by applying the filters in the requested direction; if no traversal
085 * is possible, <code>currentNode</code> is not changed.
086 */
087 public Node getCurrentNode();
088 /**
089 * The node at which the <code>TreeWalker</code> is currently positioned.
090 * <br>Alterations to the DOM tree may cause the current node to no longer
091 * be accepted by the <code>TreeWalker</code>'s associated filter.
092 * <code>currentNode</code> may also be explicitly set to any node,
093 * whether or not it is within the subtree specified by the
094 * <code>root</code> node or would be accepted by the filter and
095 * <code>whatToShow</code> flags. Further traversal occurs relative to
096 * <code>currentNode</code> even if it is not part of the current view,
097 * by applying the filters in the requested direction; if no traversal
098 * is possible, <code>currentNode</code> is not changed.
099 * @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 }