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ODFDOM is an OpenDocument Format (ODF) framework. Its purpose is to provide an easy common way to create, access and manipulate ODF files, without requiring detailed knowledge of the ODF specification. It is designed to provide the ODF developer community with an easy lightwork programming API portable to any object-oriented language. The current reference implementation is written in Java.

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/**
 * **********************************************************************
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License. You may obtain a
 * copy of the License at
 *
 * 
http://www.apache.org/licenses/LICENSE-2.0
 *
 * 
Unless required by applicable law or agreed to in writing, software distributed under the
 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * **********************************************************************
 */
package org.odftoolkit.odfdom.incubator.search;

import org.w3c.dom.Node;

/**
 * Abstract class Navigation used to navigate the document and find the matched element by the user
 * defined conditions
 */
public abstract class Navigation {

  /**
   * Return true if document still has more matched Selection when traversing the document(In other
   * words return true if getNextMatchElement() would return an element instance rather than return
   * null)
   *
   * @return true if document still has more matched Selection, and vice versa
   */
  public abstract boolean hasNext();
  // abstract public void gotoPrevious();

  /**
   * get the current Selection result
   *
   * @return the current Selection result
   */
  public abstract Selection getCurrentItem();

  /**
   * check if the element match the user defined condition
   *
   * @param element navigate this element
   * @return true if the element match the user defined condition; false if not match
   */
  public abstract boolean match(Node element);

  /**
   * get the next matched element in a whole dom tree
   *
   * @param startpoint navigate from the startpoint
   * @return the next matched element
   */
  protected Node getNextMatchElement(Node startpoint) {
    Node matchedNode = null;
    matchedNode = traverseTree(startpoint);

    Node currentpoint = startpoint;
    while ((matchedNode == null) && (currentpoint != null)) {
      Node sibling = currentpoint.getNextSibling();
      if ((sibling != null)
          && (sibling.getNodeType() == Node.TEXT_NODE || sibling.getNodeType() == Node.ELEMENT_NODE)
          && (match(sibling))) {
        matchedNode = sibling;
      }
      while ((sibling != null) && (matchedNode == null)) {
        if ((sibling.getNodeType() == Node.TEXT_NODE
            || sibling.getNodeType() == Node.ELEMENT_NODE)) {
          matchedNode = traverseTree(sibling);
        }
        sibling = sibling.getNextSibling();
        if (sibling != null && match(sibling)) {
          matchedNode = sibling;
        }
      }
      currentpoint = currentpoint.getParentNode();
    }

    return matchedNode;
  }

  /**
   * get the next matched element in a sub tree
   *
   * @param startpoint navigate from the startpoint
   * @param root the root of the sub tree
   * @return the next matched element
   */
  protected Node getNextMatchElementInTree(Node startpoint, Node root) {
    Node matchedNode = null;
    matchedNode = traverseTree(startpoint);

    Node currentpoint = startpoint;
    while ((matchedNode == null) && (currentpoint != root)) {
      Node sibling = currentpoint.getNextSibling();
      if ((sibling != null)
          && (sibling.getNodeType() == Node.TEXT_NODE || sibling.getNodeType() == Node.ELEMENT_NODE)
          && (match(sibling))) {
        matchedNode = sibling;
      }
      while ((sibling != null) && (matchedNode == null)) {
        if ((sibling.getNodeType() == Node.TEXT_NODE
            || sibling.getNodeType() == Node.ELEMENT_NODE)) {
          matchedNode = traverseTree(sibling);
        }
        sibling = sibling.getNextSibling();
        if (sibling != null && match(sibling)) {
          matchedNode = sibling;
        }
      }
      currentpoint = currentpoint.getParentNode();
    }

    return matchedNode;
  }

  private Node traverseTree(Node root) {
    Node matchedNode = null;
    if (root == null) {
      return null;
    }
    // if (match(root)) return root;

    Node node = root.getFirstChild();
    while (node != null) {
      if ((node.getNodeType() == Node.TEXT_NODE || node.getNodeType() == Node.ELEMENT_NODE)) {
        if (match(node) == true) {
          matchedNode = node;
          break;
        } else {
          matchedNode = traverseTree(node);
          if (matchedNode != null) {
            break;
          }
        }
      }
      node = node.getNextSibling();
    }
    return matchedNode;
  }
}