/* * 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 DOM Level 2 */ public interface TreeWalker { /** * The root node of the TreeWalker, 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. */ 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 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. */ 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. */ 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. * @exception DOMException * NOT_SUPPORTED_ERR: Raised if an attempt is made to set * currentNode to null. */ 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. * @return The new parent node, or null if the current node * has no parent in the TreeWalker'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. * @return The new node, or null if the current node has no * visible children in the TreeWalker'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. * @return The new node, or null if the current node has no * children in the TreeWalker'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. * @return The new node, or null if the current node has no * previous sibling. in the TreeWalker'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. * @return The new node, or null if the current node has no * next sibling. in the TreeWalker'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. * @return The new node, or null if the current node has no * previous node in the TreeWalker'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. * @return The new node, or null if the current node has no * next node in the TreeWalker's logical view. */ public Node nextNode(); }