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 * reserved comment block

 * DO NOT REMOVE OR ALTER!

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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

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package com.sun.org.apache.xml.internal.utils;

import org.w3c.dom.NamedNodeMap;

import org.w3c.dom.Node;

/**

 * This class implements a generic PrefixResolver that

 * can be used to perform prefix-to-namespace lookup

 * for the XPath object.

 * @xsl.usage general

 */

public class PrefixResolverDefault implements PrefixResolver

{

  /**

   * The context to resolve the prefix from, if the context

   * is not given.

   */

  Node m_context;

  /**

   * Construct a PrefixResolverDefault object.

   * @param xpathExpressionContext The context from

   * which XPath expression prefixes will be resolved.

   * Warning: This will not work correctly if xpathExpressionContext

   * is an attribute node.

   */

  public PrefixResolverDefault(Node xpathExpressionContext)

  {

    m_context = xpathExpressionContext;

  }

  /**

   * Given a namespace, get the corrisponding prefix.  This assumes that

   * the PrevixResolver hold's it's own namespace context, or is a namespace

   * context itself.

   * @param prefix Prefix to resolve.

   * @return Namespace that prefix resolves to, or null if prefix

   * is not bound.

   */

  public String getNamespaceForPrefix(String prefix)

  {

    return getNamespaceForPrefix(prefix, m_context);

  }

  /**

   * Given a namespace, get the corrisponding prefix.

   * Warning: This will not work correctly if namespaceContext

   * is an attribute node.

   * @param prefix Prefix to resolve.

   * @param namespaceContext Node from which to start searching for a

   * xmlns attribute that binds a prefix to a namespace.

   * @return Namespace that prefix resolves to, or null if prefix

   * is not bound.

   */

  public String getNamespaceForPrefix(String prefix,

                                      org.w3c.dom.Node namespaceContext)

  {

    Node parent = namespaceContext;

    String namespace = null;

    if (prefix.equals("xml"))

    {

      namespace = Constants.S_XMLNAMESPACEURI;

    }

    else

    {

      int type;

      while ((null != parent) && (null == namespace)

             && (((type = parent.getNodeType()) == Node.ELEMENT_NODE)

                 || (type == Node.ENTITY_REFERENCE_NODE)))

      {

        if (type == Node.ELEMENT_NODE)

        {

                if (parent.getNodeName().indexOf(prefix+":") == 0)

                        return parent.getNamespaceURI();

          NamedNodeMap nnm = parent.getAttributes();

          for (int i = 0; i < nnm.getLength(); i++)

          {

            Node attr = nnm.item(i);

            String aname = attr.getNodeName();

            boolean isPrefix = aname.startsWith("xmlns:");

            if (isPrefix || aname.equals("xmlns"))

            {

              int index = aname.indexOf(':');

              String p = isPrefix ? aname.substring(index + 1) : "";

              if (p.equals(prefix))

              {

                namespace = attr.getNodeValue();

                break;

              }

            }

          }

        }

        parent = parent.getParentNode();

      }

    }

    return namespace;

  }

  /**

   * Return the base identifier.

   *

   * @return null

   */

  public String getBaseIdentifier()

  {

    return null;

  }

        /**

         * @see PrefixResolver#handlesNullPrefixes()

         */

        public boolean handlesNullPrefixes() {

                return false;

        }

}