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* Copyright (c) 2000 World Wide Web Consortium,
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* (Massachusetts Institute of Technology, Institut National de
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* Recherche en Informatique et en Automatique, Keio University). All
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* Rights Reserved. This program is distributed under the W3C's Software
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* Intellectual Property License. This program is distributed in the
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* hope that it will be useful, but WITHOUT ANY WARRANTY; without even
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* the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* See W3C License http://www.w3.org/Consortium/Legal/ for more details.
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package org.w3c.dom.traversal;
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import org.w3c.dom.Node;
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import org.w3c.dom.DOMException;
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* <code>TreeWalker</code> objects are used to navigate a document tree or
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* subtree using the view of the document defined by their
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* <code>whatToShow</code> flags and filter (if any). Any function which
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* performs navigation using a <code>TreeWalker</code> will automatically
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* support any view defined by a <code>TreeWalker</code>.
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* <p>Omitting nodes from the logical view of a subtree can result in a
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* structure that is substantially different from the same subtree in the
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* complete, unfiltered document. Nodes that are siblings in the
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* <code>TreeWalker</code> view may be children of different, widely
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* separated nodes in the original view. For instance, consider a
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* <code>NodeFilter</code> that skips all nodes except for Text nodes and
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* the root node of a document. In the logical view that results, all text
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* nodes will be siblings and appear as direct children of the root node, no
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* matter how deeply nested the structure of the original document.
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* <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>.
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public interface TreeWalker {
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* The <code>root</code> node of the <code>TreeWalker</code>, as specified
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* when it was created.
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public Node getRoot();
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* This attribute determines which node types are presented via the
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* <code>TreeWalker</code>. The available set of constants is defined in
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* the <code>NodeFilter</code> interface. Nodes not accepted by
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* <code>whatToShow</code> will be skipped, but their children may still
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* be considered. Note that this skip takes precedence over the filter,
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public int getWhatToShow();
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* The filter used to screen nodes.
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public NodeFilter getFilter();
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* The value of this flag determines whether the children of entity
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* reference nodes are visible to the <code>TreeWalker</code>. If false,
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* these children and their descendants will be rejected. Note that
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* this rejection takes precedence over <code>whatToShow</code> and the
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* <br> To produce a view of the document that has entity references
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* expanded and does not expose the entity reference node itself, use
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* the <code>whatToShow</code> flags to hide the entity reference node
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* and set <code>expandEntityReferences</code> to true when creating the
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* <code>TreeWalker</code>. To produce a view of the document that has
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* entity reference nodes but no entity expansion, use the
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* <code>whatToShow</code> flags to show the entity reference node and
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* set <code>expandEntityReferences</code> to false.
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public boolean getExpandEntityReferences();
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* The node at which the <code>TreeWalker</code> is currently positioned.
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* <br>Alterations to the DOM tree may cause the current node to no longer
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* be accepted by the <code>TreeWalker</code>'s associated filter.
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* <code>currentNode</code> may also be explicitly set to any node,
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* whether or not it is within the subtree specified by the
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* <code>root</code> node or would be accepted by the filter and
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* <code>whatToShow</code> flags. Further traversal occurs relative to
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* <code>currentNode</code> even if it is not part of the current view,
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* by applying the filters in the requested direction; if no traversal
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* is possible, <code>currentNode</code> is not changed.
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public Node getCurrentNode();
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* The node at which the <code>TreeWalker</code> is currently positioned.
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* <br>Alterations to the DOM tree may cause the current node to no longer
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* be accepted by the <code>TreeWalker</code>'s associated filter.
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* <code>currentNode</code> may also be explicitly set to any node,
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* whether or not it is within the subtree specified by the
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* <code>root</code> node or would be accepted by the filter and
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* <code>whatToShow</code> flags. Further traversal occurs relative to
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* <code>currentNode</code> even if it is not part of the current view,
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* by applying the filters in the requested direction; if no traversal
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* is possible, <code>currentNode</code> is not changed.
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* @exception DOMException
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* NOT_SUPPORTED_ERR: Raised if an attempt is made to set
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* <code>currentNode</code> to <code>null</code>.
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public void setCurrentNode(Node currentNode)
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* Moves to and returns the closest visible ancestor node of the current
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* node. If the search for <code>parentNode</code> attempts to step
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* upward from the <code>TreeWalker</code>'s <code>root</code> node, or
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* if it fails to find a visible ancestor node, this method retains the
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* current position and returns <code>null</code>.
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* @return The new parent node, or <code>null</code> if the current node
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* has no parent in the <code>TreeWalker</code>'s logical view.
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public Node parentNode();
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* Moves the <code>TreeWalker</code> to the first visible child of the
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* current node, and returns the new node. If the current node has no
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* visible children, returns <code>null</code>, and retains the current
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* @return The new node, or <code>null</code> if the current node has no
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* visible children in the <code>TreeWalker</code>'s logical view.
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public Node firstChild();
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* Moves the <code>TreeWalker</code> to the last visible child of the
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* current node, and returns the new node. If the current node has no
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* visible children, returns <code>null</code>, and retains the current
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* @return The new node, or <code>null</code> if the current node has no
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* children in the <code>TreeWalker</code>'s logical view.
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public Node lastChild();
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* Moves the <code>TreeWalker</code> to the previous sibling of the
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* current node, and returns the new node. If the current node has no
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* visible previous sibling, returns <code>null</code>, and retains the
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* @return The new node, or <code>null</code> if the current node has no
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* previous sibling. in the <code>TreeWalker</code>'s logical view.
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public Node previousSibling();
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* Moves the <code>TreeWalker</code> to the next sibling of the current
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* node, and returns the new node. If the current node has no visible
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* next sibling, returns <code>null</code>, and retains the current node.
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* @return The new node, or <code>null</code> if the current node has no
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* next sibling. in the <code>TreeWalker</code>'s logical view.
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public Node nextSibling();
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* Moves the <code>TreeWalker</code> to the previous visible node in
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* document order relative to the current node, and returns the new
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* node. If the current node has no previous node, or if the search for
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* <code>previousNode</code> attempts to step upward from the
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* <code>TreeWalker</code>'s <code>root</code> node, returns
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* <code>null</code>, and retains the current node.
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* @return The new node, or <code>null</code> if the current node has no
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* previous node in the <code>TreeWalker</code>'s logical view.
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public Node previousNode();
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* Moves the <code>TreeWalker</code> to the next visible node in document
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* order relative to the current node, and returns the new node. If the
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* current node has no next node, or if the search for nextNode attempts
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* to step upward from the <code>TreeWalker</code>'s <code>root</code>
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* node, returns <code>null</code>, and retains the current node.
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* @return The new node, or <code>null</code> if the current node has no
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* next node in the <code>TreeWalker</code>'s logical view.
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public Node nextNode();
added
removed
org/w3c/dom/traversal/TreeWalker.java
