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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/SimpleNamespaceContext.java,v 1.14 2005/06/19 19:24:26 elharo Exp $
3    * $Revision: 1.14 $
4    * $Date: 2005/06/19 19:24:26 $
5    *
6    * ====================================================================
7    *
8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions
13   * are met:
14   * 
15   * 1. Redistributions of source code must retain the above copyright
16   *    notice, this list of conditions, and the following disclaimer.
17   *
18   * 2. Redistributions in binary form must reproduce the above copyright
19   *    notice, this list of conditions, and the disclaimer that follows 
20   *    these conditions in the documentation and/or other materials 
21   *    provided with the distribution.
22   *
23   * 3. The name "Jaxen" must not be used to endorse or promote products
24   *    derived from this software without prior written permission.  For
25   *    written permission, please contact license@jaxen.org.
26   * 
27   * 4. Products derived from this software may not be called "Jaxen", nor
28   *    may "Jaxen" appear in their name, without prior written permission
29   *    from the Jaxen Project Management (pm@jaxen.org).
30   * 
31   * In addition, we request (but do not require) that you include in the 
32   * end-user documentation provided with the redistribution and/or in the 
33   * software itself an acknowledgement equivalent to the following:
34   *     "This product includes software developed by the
35   *      Jaxen Project (http://www.jaxen.org/)."
36   * Alternatively, the acknowledgment may be graphical using the logos 
37   * available at http://www.jaxen.org/
38   *
39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50   * SUCH DAMAGE.
51   *
52   * ====================================================================
53   * This software consists of voluntary contributions made by many 
54   * individuals on behalf of the Jaxen Project and was originally 
55   * created by bob mcwhirter <bob@werken.com> and 
56   * James Strachan <jstrachan@apache.org>.  For more information on the 
57   * Jaxen Project, please see <http://www.jaxen.org/>.
58   * 
59   * $Id: SimpleNamespaceContext.java,v 1.14 2005/06/19 19:24:26 elharo Exp $
60   */
61  
62  
63  package org.jaxen;
64  
65  import java.io.Serializable;
66  import java.util.HashMap;
67  import java.util.Iterator;
68  import java.util.Map;
69  
70  /***
71   *  Provides mappings from namespace prefix to namespace URI to the XPath
72   *  engine.
73   */
74  public class SimpleNamespaceContext implements NamespaceContext, Serializable
75  {
76      
77      // XXX should this prebind the xml prefix?
78      private Map namespaces;
79  
80      /***
81       * Creates a new empty namespace context.
82       */
83      public SimpleNamespaceContext()
84      {
85          this.namespaces = new HashMap();
86      }
87  
88      /***
89       * Creates a new namespace context pre-populated with the specified bindings. 
90       * 
91       * @param namespaces the initial namespace bindings in scope. The keys in this
92       *     must be strings containing the prefixes and the values are strings
93       *     containing the namespace URIs.
94       *     
95       * @throws NullPointerException if the argument is null   
96       */
97      public SimpleNamespaceContext(Map namespaces)
98      {
99          // FIXME this is dangerous. We should check that
100         // the contents are strings.
101         this.namespaces = new HashMap(namespaces);
102     }
103 
104     /***
105      *  Adds all the namespace declarations that are in scope on the given
106      *  element. In the case of an XSLT stylesheet, this would be the element
107      *  that has the XPath expression in one of its attributes; e.g.
108      *  <code>&lt;xsl:if test="condition/xpath/expression"&gt;</code>.
109      *
110      *  @param nav  the navigator for use in conjunction with
111      *              <code>element</code>
112      *  @param element the element to copy the namespaces from
113      *  @throws UnsupportedAxisException if the navigator does not support the 
114      *     namespace axis
115      */
116     public void addElementNamespaces( Navigator nav, Object element )
117         throws UnsupportedAxisException
118     {
119         Iterator namespaceAxis = nav.getNamespaceAxisIterator( element );
120 
121         while ( namespaceAxis.hasNext() ) {
122             Object namespace = namespaceAxis.next();
123             String prefix = nav.getNamespacePrefix( namespace );
124             String uri = nav.getNamespaceStringValue( namespace );
125             if ( translateNamespacePrefixToUri(prefix) == null ) {
126                 addNamespace( prefix, uri );
127             }
128         }
129     }    
130 
131     // ???? What if prefix or URI is null, or both?
132     /***
133      * Binds a prefix to a URI in this context.
134      * 
135      * @param prefix the namespace prefix
136      * @param URI    the namespace URI
137      */
138     public void addNamespace(String prefix, String URI)
139     {
140         this.namespaces.put( prefix, URI );
141     }
142 
143     public String translateNamespacePrefixToUri(String prefix)
144     {
145         if ( this.namespaces.containsKey( prefix ) )
146         {
147             return (String) this.namespaces.get( prefix );
148         }
149 
150         return null;
151     }
152 }