code: /*
   * 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.dtm.ref;
  
  import org.apache.xml.dtm.DTM;
  
  import org.w3c.dom.DOMException;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  
  /**
   * DTMNamedNodeMap is a quickie (as opposed to quick) implementation of the DOM's
   * NamedNodeMap interface, intended to support DTMProxy's getAttributes()
   * call.
   * <p>
   * ***** Note: this does _not_ current attempt to cache any of the data;
   * if you ask for attribute 27 and then 28, you'll have to rescan the first
   * 27. It should probably at least keep track of the last one retrieved,
   * and possibly buffer the whole array.
   * <p>
   * ***** Also note that there's no fastpath for the by-name query; we search
   * linearly until we find it or fail to find it. Again, that could be
   * optimized at some cost in object creation/storage.
   * @xsl.usage internal
   */
  public class DTMNamedNodeMap implements NamedNodeMap
  {
  
    /** The DTM for this node. */
    DTM dtm;
  
    /** The DTM element handle. */
    int element;
  
    /** The number of nodes in this map. */
    short m_count = -1;
  
    /**
     * Create a getAttributes NamedNodeMap for a given DTM element node
     *
     * @param dtm The DTM Reference, must be non-null.
     * @param element The DTM element handle.
     */
    public DTMNamedNodeMap(DTM dtm, int element)
    {
      this.dtm = dtm;
      this.element = element;
    }
  
    /**
     * Return the number of Attributes on this Element
     *
     * @return The number of nodes in this map.
     */
    public int getLength()
    {
  
      if (m_count == -1)
      {
        short count = 0;
  
        for (int n = dtm.getFirstAttribute(element); n != -1;
                n = dtm.getNextAttribute(n))
        {
          ++count;
        }
  
        m_count = count;
      }
  
      return (int) m_count;
    }
  
    /**
     * Retrieves a node specified by name.
     * @param name The <code>nodeName</code> of a node to retrieve.
     * @return A <code>Node</code> (of any type) with the specified
     *   <code>nodeName</code>, or <code>null</code> if it does not identify
     *   any node in this map.
     */
    public Node getNamedItem(String name)
    {
  
      for (int n = dtm.getFirstAttribute(element); n != DTM.NULL;
              n = dtm.getNextAttribute(n))
      {
        if (dtm.getNodeName(n).equals(name))
          return dtm.getNode(n);
      }
  
      return null;
    }
  
    /**
     * Returns the <code>index</code>th item in the map. If <code>index</code>
     * is greater than or equal to the number of nodes in this map, this
     * returns <code>null</code>.
     * @param i The index of the requested item.
     * @return The node at the <code>index</code>th position in the map, or
     *   <code>null</code> if that is not a valid index.
     */
    public Node item(int i)
    {
  
      int count = 0;
  
      for (int n = dtm.getFirstAttribute(element); n != -1;
              n = dtm.getNextAttribute(n))
      {
        if (count == i)
          return dtm.getNode(n);
        else
          ++count;
      }
  
      return null;
    }
  
    /**
     * Adds a node using its <code>nodeName</code> attribute. If a node with
     * that name is already present in this map, it is replaced by the new
     * one.
     * <br>As the <code>nodeName</code> attribute is used to derive the name
     * which the node must be stored under, multiple nodes of certain types
     * (those that have a "special" string value) cannot be stored as the
     * names would clash. This is seen as preferable to allowing nodes to be
     * aliased.
     * @param newNode node to store in this map. The node will later be
     *   accessible using the value of its <code>nodeName</code> attribute.
     *
     * @return If the new <code>Node</code> replaces an existing node the
     *   replaced <code>Node</code> is returned, otherwise <code>null</code>
     *   is returned.
     * @exception DOMException
     *   WRONG_DOCUMENT_ERR: Raised if <code>arg</code> was created from a
     *   different document than the one that created this map.
     *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
     *   <br>INUSE_ATTRIBUTE_ERR: Raised if <code>arg</code> is an
     *   <code>Attr</code> that is already an attribute of another
     *   <code>Element</code> object. The DOM user must explicitly clone
     *   <code>Attr</code> nodes to re-use them in other elements.
     */
    public Node setNamedItem(Node newNode)
    {
      throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
    }
  
    /**
     * Removes a node specified by name. When this map contains the attributes
     * attached to an element, if the removed attribute is known to have a
     * default value, an attribute immediately appears containing the
     * default value as well as the corresponding namespace URI, local name,
     * and prefix when applicable.
     * @param name The <code>nodeName</code> of the node to remove.
     *
     * @return The node removed from this map if a node with such a name
     *   exists.
     * @exception DOMException
     *   NOT_FOUND_ERR: Raised if there is no node named <code>name</code> in
     *   this map.
     *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
     */
    public Node removeNamedItem(String name)
    {
      throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
    }
  
    /**
     * Retrieves a node specified by local name and namespace URI. HTML-only
     * DOM implementations do not need to implement this method.
     * @param namespaceURI The namespace URI of the node to retrieve.
     * @param localName The local name of the node to retrieve.
     *
     * @return A <code>Node</code> (of any type) with the specified local
     *   name and namespace URI, or <code>null</code> if they do not
     *   identify any node in this map.
     * @since DOM Level 2
     */
    public Node getNamedItemNS(String namespaceURI, String localName)
    {
         Node retNode = null;
         for (int n = dtm.getFirstAttribute(element); n != DTM.NULL;
                         n = dtm.getNextAttribute(n))
         {
           if (localName.equals(dtm.getLocalName(n)))
           {
             String nsURI = dtm.getNamespaceURI(n); 
             if ((namespaceURI == null && nsURI == null)
                    || (namespaceURI != null && namespaceURI.equals(nsURI)))
             {
               retNode = dtm.getNode(n);
               break;
             }
           }
         }
         return retNode;
    }
  
    /**
     * Adds a node using its <code>namespaceURI</code> and
     * <code>localName</code>. If a node with that namespace URI and that
     * local name is already present in this map, it is replaced by the new
     * one.
     * <br>HTML-only DOM implementations do not need to implement this method.
     * @param arg A node to store in this map. The node will later be
     *   accessible using the value of its <code>namespaceURI</code> and
     *   <code>localName</code> attributes.
     *
     * @return If the new <code>Node</code> replaces an existing node the
     *   replaced <code>Node</code> is returned, otherwise <code>null</code>
     *   is returned.
     * @exception DOMException
     *   WRONG_DOCUMENT_ERR: Raised if <code>arg</code> was created from a
     *   different document than the one that created this map.
     *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
     *   <br>INUSE_ATTRIBUTE_ERR: Raised if <code>arg</code> is an
     *   <code>Attr</code> that is already an attribute of another
     *   <code>Element</code> object. The DOM user must explicitly clone
     *   <code>Attr</code> nodes to re-use them in other elements.
     * @since DOM Level 2
     */
    public Node setNamedItemNS(Node arg) throws DOMException
    {
      throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
    }
  
    /**
     * Removes a node specified by local name and namespace URI. A removed
     * attribute may be known to have a default value when this map contains
     * the attributes attached to an element, as returned by the attributes
     * attribute of the <code>Node</code> interface. If so, an attribute
     * immediately appears containing the default value as well as the
     * corresponding namespace URI, local name, and prefix when applicable.
     * <br>HTML-only DOM implementations do not need to implement this method.
     * 
     * @param namespaceURI The namespace URI of the node to remove.
     * @param localName The local name of the node to remove.
     *
     * @return The node removed from this map if a node with such a local
     *   name and namespace URI exists.
     * @exception DOMException
     *   NOT_FOUND_ERR: Raised if there is no node with the specified
     *   <code>namespaceURI</code> and <code>localName</code> in this map.
     *   <br>NO_MODIFICATION_ALLOWED_ERR: Raised if this map is readonly.
     * @since DOM Level 2
     */
    public Node removeNamedItemNS(String namespaceURI, String localName)
            throws DOMException
    {
      throw new DTMException(DTMException.NO_MODIFICATION_ALLOWED_ERR);
    }
  
    /**
     * Simple implementation of DOMException.
     * @xsl.usage internal
     */
    public static class DTMException extends org.w3c.dom.DOMException
    {
            static final long serialVersionUID = -8290238117162437678L;
      /**
       * Constructs a DOM/DTM exception.
       *
       * @param code
       * @param message
       */
      public DTMException(short code, String message)
      {
        super(code, message);
      }
  
      /**
       * Constructor DTMException
       *
       *
       * @param code
       */
      public DTMException(short code)
      {
        super(code, "");
      }
    }
  }
  