/*
* 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 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();
}
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