Java tutorial
/* * 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; /** * <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 <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 * <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. */ public NodeFilter getFilter(); /** * 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 <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 <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 <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 <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 <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 <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 <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 <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 <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(); }