/*
 * 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>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>TreeWalker</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;

}
