content: /*
   * $Header$
   * $Revision$
   * $Date$
   *
   * ====================================================================
   *
   * Copyright 2000-2002 bob mcwhirter & James Strachan.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   * 
   *   * Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer.
   * 
   *   * Redistributions in binary form must reproduce the above copyright
   *     notice, this list of conditions and the following disclaimer in the
   *     documentation and/or other materials provided with the distribution.
   * 
   *   * Neither the name of the Jaxen Project nor the names of its
   *     contributors may be used to endorse or promote products derived 
   *     from this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
   * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
   * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * ====================================================================
   * This software consists of voluntary contributions made by many 
   * individuals on behalf of the Jaxen Project and was originally 
   * created by bob mcwhirter <bob@werken.com> and 
   * James Strachan <jstrachan@apache.org>.  For more information on the 
   * Jaxen Project, please see <http://www.jaxen.org/>.
   * 
   * $Id$
   */
  
  
  package org.jaxen;
  
  import java.io.Serializable;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  /**
   *  Provides mappings from namespace prefix to namespace URI to the XPath
   *  engine.
   */
  public class SimpleNamespaceContext implements NamespaceContext, Serializable
  {
      
      /**
       * 
       */
      private static final long serialVersionUID = -808928409643497762L;
      // XXX should this prebind the xml prefix?
      private Map namespaces;
  
      /**
       * Creates a new empty namespace context.
       */
      public SimpleNamespaceContext()
      {
          this.namespaces = new HashMap();
      }
  
      /**
       * Creates a new namespace context pre-populated with the specified bindings. 
       * 
       * @param namespaces the initial namespace bindings in scope. The keys in this
       *     must be strings containing the prefixes and the values are strings
       *     containing the namespace URIs.
       *     
       * @throws NullPointerException if the argument is null   
       * @throws ClassCastException if any keys or values in the map are not strings   
       */
      public SimpleNamespaceContext(Map namespaces)
      {
          Iterator entries = namespaces.entrySet().iterator();
          while (entries.hasNext()) {
              Map.Entry entry = (Map.Entry) entries.next();
              if (! (entry.getKey() instanceof String)
                || ! (entry.getValue() instanceof String)) {
                  throw new ClassCastException("Non-string namespace binding");
              }
          }
          this.namespaces = new HashMap(namespaces);
      }
  
      /**
       *  Adds all the namespace declarations that are in scope on the given
       *  element. In the case of an XSLT stylesheet, this would be the element
       *  that has the XPath expression in one of its attributes; e.g.
       *  <code>&lt;xsl:if test="condition/xpath/expression"&gt;</code>.
       *
       *  @param nav  the navigator for use in conjunction with
       *              <code>element</code>
       *  @param element the element to copy the namespaces from
       *  @throws UnsupportedAxisException if the navigator does not support the 
       *     namespace axis
       */
      public void addElementNamespaces( Navigator nav, Object element )
          throws UnsupportedAxisException
      {
          Iterator namespaceAxis = nav.getNamespaceAxisIterator( element );
  
          while ( namespaceAxis.hasNext() ) {
              Object namespace = namespaceAxis.next();
              String prefix = nav.getNamespacePrefix( namespace );
              String uri = nav.getNamespaceStringValue( namespace );
              if ( translateNamespacePrefixToUri(prefix) == null ) {
                  addNamespace( prefix, uri );
              }
          }
      }    
  
      // ???? What if prefix or URI is null, or both?
      /**
       * Binds a prefix to a URI in this context.
       * 
       * @param prefix the namespace prefix
       * @param URI    the namespace URI
       */
      public void addNamespace(String prefix, String URI)
      {
          this.namespaces.put( prefix, URI );
      }
  
      public String translateNamespacePrefixToUri(String prefix)
      {
          if ( this.namespaces.containsKey( prefix ) )
          {
              return (String) this.namespaces.get( prefix );
          }
  
          return null;
      }
  }
  