content: package org.w3c.dom.traversal;
  
  import org.w3c.dom.Node;
  import org.w3c.dom.DOMException;
  /**
   * <code>DocumentTraversal</code> contains methods that create
   * <code>NodeIterators</code> and <code>TreeWalkers</code> to traverse a
   * node and its children in document order (depth first, pre-order
   * traversal, which is equivalent to the order in which the start tags occur
   * in the text representation of the document). In DOMs which support the
   * Traversal feature, <code>DocumentTraversal</code> will be implemented by
   * the same objects that implement the Document interface.
   * <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 DocumentTraversal {
      /**
       * Create a new <code>NodeIterator</code> over the subtree rooted at the
       * specified node.
       * @param root The node which will be iterated together with its
       *   children. The <code>NodeIterator</code> is initially positioned
       *   just before this node. The <code>whatToShow</code> flags and the
       *   filter, if any, are not considered when setting this position. The
       *   root must not be <code>null</code>.
       * @param whatToShow This flag specifies which node types may appear in
       *   the logical view of the tree presented by the
       *   <code>NodeIterator</code>. See the description of
       *   <code>NodeFilter</code> for the set of possible <code>SHOW_</code>
       *   values.These flags can be combined using <code>OR</code>.
       * @param filter The <code>NodeFilter</code> to be used with this
       *   <code>NodeIterator</code>, or <code>null</code> to indicate no
       *   filter.
       * @param entityReferenceExpansion The value of this flag determines
       *   whether entity reference nodes are expanded.
       * @return The newly created <code>NodeIterator</code>.
       * @exception DOMException
       *   NOT_SUPPORTED_ERR: Raised if the specified <code>root</code> is
       *   <code>null</code>.
       */
      public NodeIterator createNodeIterator(Node root,
                                             int whatToShow,
                                             NodeFilter filter,
                                             boolean entityReferenceExpansion)
              throws DOMException;
      /**
       * Create a new <code>TreeWalker</code> over the subtree rooted at the
       * specified node.
       * @param root The node which will serve as the <code>root</code> for the
       *   <code>TreeWalker</code>. The <code>whatToShow</code> flags and the
       *   <code>NodeFilter</code> are not considered when setting this value;
       *   any node type will be accepted as the <code>root</code>. The
       *   <code>currentNode</code> of the <code>TreeWalker</code> is
       *   initialized to this node, whether or not it is visible. The
       *   <code>root</code> functions as a stopping point for traversal
       *   methods that look upward in the document structure, such as
       *   <code>parentNode</code> and nextNode. The <code>root</code> must
       *   not be <code>null</code>.
       * @param whatToShow This flag specifies which node types may appear in
       *   the logical view of the tree presented by the
       *   <code>TreeWalker</code>. See the description of
       *   <code>NodeFilter</code> for the set of possible <code>SHOW_</code>
       *   values.These flags can be combined using <code>OR</code>.
       * @param filter The <code>NodeFilter</code> to be used with this
       *   <code>TreeWalker</code>, or <code>null</code> to indicate no filter.
       * @param entityReferenceExpansion If this flag is false, the contents of
       *   <code>EntityReference</code> nodes are not presented in the logical
       *   view.
       * @return The newly created <code>TreeWalker</code>.
       * @exception DOMException
       *    NOT_SUPPORTED_ERR: Raised if the specified <code>root</code> is
       *   <code>null</code>.
       */
      public TreeWalker createTreeWalker(Node root,
                                         int whatToShow,
                                         NodeFilter filter,
                                         boolean entityReferenceExpansion)
              throws DOMException;
  }