/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * This file is available under and governed by the GNU General Public
 * License version 2 only, as published by the Free Software Foundation.
 * However, the following notice accompanied the original version of this
 * file and, per its terms, should not be removed:
 *
 * Copyright (c) 2000 World Wide Web Consortium,
 * (Massachusetts Institute of Technology, Institut National de
 * Recherche en Informatique et en Automatique, Keio University). All
 * Rights Reserved. This program is distributed under the W3C's Software
 * Intellectual Property License. This program is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY; without even
 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.
 * See W3C License http://www.w3.org/Consortium/Legal/ for more details.
 */

package org.w3c.dom.traversal;

import org.w3c.dom.Node;
import org.w3c.dom.DOMException;

TreeWalker objects are used to navigate a document tree or subtree using the view of the document defined by their whatToShow flags and filter (if any). Any function which performs navigation using a TreeWalker will automatically support any view defined by a TreeWalker.

Omitting nodes from the logical view of a subtree can result in a structure that is substantially different from the same subtree in the complete, unfiltered document. Nodes that are siblings in the TreeWalker view may be children of different, widely separated nodes in the original view. For instance, consider a NodeFilter that skips all nodes except for Text nodes and the root node of a document. In the logical view that results, all text nodes will be siblings and appear as direct children of the root node, no matter how deeply nested the structure of the original document.

See also the Document Object Model (DOM) Level 2 Traversal and Range Specification.

Since:9, DOM Level 2
/** * <code>TreeWalker</code> objects are used to navigate a document tree or * subtree using the view of the document defined by their * <code>whatToShow</code> flags and filter (if any). Any function which * performs navigation using a <code>TreeWalker</code> will automatically * support any view defined by a <code>TreeWalker</code>. * <p>Omitting nodes from the logical view of a subtree can result in a * structure that is substantially different from the same subtree in the * complete, unfiltered document. Nodes that are siblings in the * <code>TreeWalker</code> view may be children of different, widely * separated nodes in the original view. For instance, consider a * <code>NodeFilter</code> that skips all nodes except for Text nodes and * the root node of a document. In the logical view that results, all text * nodes will be siblings and appear as direct children of the root node, no * matter how deeply nested the structure of the original document. * <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>. * @since 9, DOM Level 2 */
public interface TreeWalker {
The root node of the TreeWalker, as specified when it was created.
/** * The <code>root</code> node of the <code>TreeWalker</code>, as specified * when it was created. */
public Node getRoot();
This attribute determines which node types are presented via the TreeWalker. The available set of constants is defined in the NodeFilter interface. Nodes not accepted by whatToShow will be skipped, but their children may still be considered. Note that this skip takes precedence over the filter, if any.
/** * This attribute determines which node types are presented via the * <code>TreeWalker</code>. The available set of constants is defined in * the <code>NodeFilter</code> interface. Nodes not accepted by * <code>whatToShow</code> will be skipped, but their children may still * be considered. Note that this skip takes precedence over the filter, * if any. */
public int getWhatToShow();
The filter used to screen nodes.
/** * The filter used to screen nodes. */
public NodeFilter getFilter();
The value of this flag determines whether the children of entity reference nodes are visible to the TreeWalker. If false, these children and their descendants will be rejected. Note that this rejection takes precedence over whatToShow and the filter, if any.
To produce a view of the document that has entity references expanded and does not expose the entity reference node itself, use the whatToShow flags to hide the entity reference node and set expandEntityReferences to true when creating the TreeWalker. To produce a view of the document that has entity reference nodes but no entity expansion, use the whatToShow flags to show the entity reference node and set expandEntityReferences to false.
/** * The value of this flag determines whether the children of entity * reference nodes are visible to the <code>TreeWalker</code>. If false, * these children and their descendants will be rejected. Note that * this rejection takes precedence over <code>whatToShow</code> and the * filter, if any. * <br> To produce a view of the document that has entity references * expanded and does not expose the entity reference node itself, use * the <code>whatToShow</code> flags to hide the entity reference node * and set <code>expandEntityReferences</code> to true when creating the * <code>TreeWalker</code>. To produce a view of the document that has * entity reference nodes but no entity expansion, use the * <code>whatToShow</code> flags to show the entity reference node and * set <code>expandEntityReferences</code> to false. */
public boolean getExpandEntityReferences();
The node at which the TreeWalker is currently positioned.
Alterations to the DOM tree may cause the current node to no longer be accepted by the TreeWalker's associated filter. currentNode may also be explicitly set to any node, whether or not it is within the subtree specified by the root node or would be accepted by the filter and whatToShow flags. Further traversal occurs relative to currentNode even if it is not part of the current view, by applying the filters in the requested direction; if no traversal is possible, currentNode is not changed.
/** * The node at which the <code>TreeWalker</code> is currently positioned. * <br>Alterations to the DOM tree may cause the current node to no longer * be accepted by the <code>TreeWalker</code>'s associated filter. * <code>currentNode</code> may also be explicitly set to any node, * whether or not it is within the subtree specified by the * <code>root</code> node or would be accepted by the filter and * <code>whatToShow</code> flags. Further traversal occurs relative to * <code>currentNode</code> even if it is not part of the current view, * by applying the filters in the requested direction; if no traversal * is possible, <code>currentNode</code> is not changed. */
public Node getCurrentNode();
The node at which the TreeWalker is currently positioned.
Alterations to the DOM tree may cause the current node to no longer be accepted by the TreeWalker's associated filter. currentNode may also be explicitly set to any node, whether or not it is within the subtree specified by the root node or would be accepted by the filter and whatToShow flags. Further traversal occurs relative to currentNode even if it is not part of the current view, by applying the filters in the requested direction; if no traversal is possible, currentNode is not changed.
Throws:
  • DOMException – NOT_SUPPORTED_ERR: Raised if an attempt is made to set currentNode to null.
/** * The node at which the <code>TreeWalker</code> is currently positioned. * <br>Alterations to the DOM tree may cause the current node to no longer * be accepted by the <code>TreeWalker</code>'s associated filter. * <code>currentNode</code> may also be explicitly set to any node, * whether or not it is within the subtree specified by the * <code>root</code> node or would be accepted by the filter and * <code>whatToShow</code> flags. Further traversal occurs relative to * <code>currentNode</code> even if it is not part of the current view, * by applying the filters in the requested direction; if no traversal * is possible, <code>currentNode</code> is not changed. * @exception DOMException * NOT_SUPPORTED_ERR: Raised if an attempt is made to set * <code>currentNode</code> to <code>null</code>. */
public void setCurrentNode(Node currentNode) throws DOMException;
Moves to and returns the closest visible ancestor node of the current node. If the search for parentNode attempts to step upward from the TreeWalker's root node, or if it fails to find a visible ancestor node, this method retains the current position and returns null.
Returns:The new parent node, or null if the current node has no parent in the TreeWalker's logical view.
/** * Moves to and returns the closest visible ancestor node of the current * node. If the search for <code>parentNode</code> attempts to step * upward from the <code>TreeWalker</code>'s <code>root</code> node, or * if it fails to find a visible ancestor node, this method retains the * current position and returns <code>null</code>. * @return The new parent node, or <code>null</code> if the current node * has no parent in the <code>TreeWalker</code>'s logical view. */
public Node parentNode();
Moves the TreeWalker to the first visible child of the current node, and returns the new node. If the current node has no visible children, returns null, and retains the current node.
Returns:The new node, or null if the current node has no visible children in the TreeWalker's logical view.
/** * Moves the <code>TreeWalker</code> to the first visible child of the * current node, and returns the new node. If the current node has no * visible children, returns <code>null</code>, and retains the current * node. * @return The new node, or <code>null</code> if the current node has no * visible children in the <code>TreeWalker</code>'s logical view. */
public Node firstChild();
Moves the TreeWalker to the last visible child of the current node, and returns the new node. If the current node has no visible children, returns null, and retains the current node.
Returns:The new node, or null if the current node has no children in the TreeWalker's logical view.
/** * Moves the <code>TreeWalker</code> to the last visible child of the * current node, and returns the new node. If the current node has no * visible children, returns <code>null</code>, and retains the current * node. * @return The new node, or <code>null</code> if the current node has no * children in the <code>TreeWalker</code>'s logical view. */
public Node lastChild();
Moves the TreeWalker to the previous sibling of the current node, and returns the new node. If the current node has no visible previous sibling, returns null, and retains the current node.
Returns:The new node, or null if the current node has no previous sibling. in the TreeWalker's logical view.
/** * Moves the <code>TreeWalker</code> to the previous sibling of the * current node, and returns the new node. If the current node has no * visible previous sibling, returns <code>null</code>, and retains the * current node. * @return The new node, or <code>null</code> if the current node has no * previous sibling. in the <code>TreeWalker</code>'s logical view. */
public Node previousSibling();
Moves the TreeWalker to the next sibling of the current node, and returns the new node. If the current node has no visible next sibling, returns null, and retains the current node.
Returns:The new node, or null if the current node has no next sibling. in the TreeWalker's logical view.
/** * Moves the <code>TreeWalker</code> to the next sibling of the current * node, and returns the new node. If the current node has no visible * next sibling, returns <code>null</code>, and retains the current node. * @return The new node, or <code>null</code> if the current node has no * next sibling. in the <code>TreeWalker</code>'s logical view. */
public Node nextSibling();
Moves the TreeWalker to the previous visible node in document order relative to the current node, and returns the new node. If the current node has no previous node, or if the search for previousNode attempts to step upward from the TreeWalker's root node, returns null, and retains the current node.
Returns:The new node, or null if the current node has no previous node in the TreeWalker's logical view.
/** * Moves the <code>TreeWalker</code> to the previous visible node in * document order relative to the current node, and returns the new * node. If the current node has no previous node, or if the search for * <code>previousNode</code> attempts to step upward from the * <code>TreeWalker</code>'s <code>root</code> node, returns * <code>null</code>, and retains the current node. * @return The new node, or <code>null</code> if the current node has no * previous node in the <code>TreeWalker</code>'s logical view. */
public Node previousNode();
Moves the TreeWalker to the next visible node in document order relative to the current node, and returns the new node. If the current node has no next node, or if the search for nextNode attempts to step upward from the TreeWalker's root node, returns null, and retains the current node.
Returns:The new node, or null if the current node has no next node in the TreeWalker's logical view.
/** * Moves the <code>TreeWalker</code> to the next visible node in document * order relative to the current node, and returns the new node. If the * current node has no next node, or if the search for nextNode attempts * to step upward from the <code>TreeWalker</code>'s <code>root</code> * node, returns <code>null</code>, and retains the current node. * @return The new node, or <code>null</code> if the current node has no * next node in the <code>TreeWalker</code>'s logical view. */
public Node nextNode(); }