/*
 * 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.
 */
/*
 * $Id$
 */
package org.apache.xml.serializer.utils;

import org.w3c.dom.Node;

/**
 * This class provides a DOM level 2 "helper", which provides services currently 
 * not provided be the DOM standard.
 * 
 * This class is a copy of the one in org.apache.xml.utils. 
 * It exists to cut the serializers dependancy on that package.
 * 
 * The differences from the original class are:
 * it doesn't extend DOMHelper, not depricated, 
 * dropped method isNodeAfter(Node node1, Node node2)
 * dropped method parse(InputSource)
 * dropped method supportSAX()
 * dropped method setDocument(doc) 
 * dropped method checkNode(Node)
 * dropped method getDocument()
 * dropped method getElementByID(String id, Document doc)
 * dropped method getParentOfNode(Node node)
 * dropped field Document m_doc;
 * made class non-public
 *   
 * This class is not a public API, it is only public because it is 
 * used in org.apache.xml.serializer.
 * 
 * @xsl.usage internal
 */
public final class DOM2Helper
{

  /**
   * Construct an instance.
   */
  public DOM2Helper(){}

  /**
   * Returns the local name of the given node, as defined by the
   * XML Namespaces specification. This is prepared to handle documents
   * built using DOM Level 1 methods by falling back upon explicitly
   * parsing the node name.
   *
   * @param n Node to be examined
   *
   * @return String containing the local name, or null if the node
   * was not assigned a Namespace.
   */
  public String getLocalNameOfNode(Node n)
  {

    String name = n.getLocalName();

    return (null == name) ? getLocalNameOfNodeFallback(n) : name;
  }
  
  /**
   * Returns the local name of the given node. If the node's name begins
   * with a namespace prefix, this is the part after the colon; otherwise
   * it's the full node name.
   * 
   * This method is copied from org.apache.xml.utils.DOMHelper
   *
   * @param n the node to be examined.
   *
   * @return String containing the Local Name
   */
  private String getLocalNameOfNodeFallback(Node n)
  {

    String qname = n.getNodeName();
    int index = qname.indexOf(':');

    return (index < 0) ? qname : qname.substring(index + 1);
  }

  /**
   * Returns the Namespace Name (Namespace URI) for the given node.
   * In a Level 2 DOM, you can ask the node itself. Note, however, that
   * doing so conflicts with our decision in getLocalNameOfNode not
   * to trust the that the DOM was indeed created using the Level 2
   * methods. If Level 1 methods were used, these two functions will
   * disagree with each other.
   * <p>
   * TODO: Reconcile with getLocalNameOfNode.
   *
   * @param n Node to be examined
   *
   * @return String containing the Namespace URI bound to this DOM node
   * at the time the Node was created.
   */
  public String getNamespaceOfNode(Node n)
  {
    return n.getNamespaceURI();
  }

  /** Field m_useDOM2getNamespaceURI is a compile-time flag which
   *  gates some of the parser options used to build a DOM -- but 
   * that code is commented out at this time and nobody else
   * references it, so I've commented this out as well. */
  //private boolean m_useDOM2getNamespaceURI = false;
}