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,
- * they 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.
- * @exception DOMException
- * NOT_SUPPORTED_ERR: Raised if an attempt is made to set
- * currentNode to null.
- */
- public Node getCurrentNode();
- 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();
-
-}