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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/SimpleVariableContext.java,v 1.12 2005/04/06 09:21:43 elharo Exp $
3    * $Revision: 1.12 $
4    * $Date: 2005/04/06 09:21:43 $
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: SimpleVariableContext.java,v 1.12 2005/04/06 09:21:43 elharo Exp $
60   */
61  
62  
63  package org.jaxen;
64  
65  import java.io.Serializable;
66  import java.util.HashMap;
67  import java.util.Map;
68  
69  /*** Simple default implementation for <code>VariableContext</code>.
70   *
71   *  <p>
72   *  This is a simple table-based key-lookup implementation
73   *  for <code>VariableContext</code> which can be programmatically
74   *  extended by setting additional variables.
75   *  </p>
76   *
77   *  @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
78   */
79  public class SimpleVariableContext implements VariableContext, Serializable
80  {
81      /*** Table of variable bindings. */
82      private Map variables;
83  
84      /*** Construct.
85       *
86       *  <p>
87       *  Construct with an empty variable lookup table.
88       *  </p>
89       */
90      public SimpleVariableContext()
91      {
92          variables = new HashMap();
93      }
94  
95      /*** Set the value associated with a variable.
96       *
97       *  <p>
98       *  This method sets a variable that is 
99       *  associated with any particular namespace.
100      *  These variables appear such as <code>$prefix:foo</code>
101      *  in an XPath expression.  Prefix to URI resolution
102      *  is the responsibility of a <code>NamespaceContext</code>.
103      *  Variables within a <code>VariableContext</code> are
104      *  referred to purely based upon their namespace URI,
105      *  if any.
106      *  </p>
107      *
108      *  @param namespaceURI the namespace URI of the variable
109      *  @param localName the local name of the variable
110      *  @param value The value to be bound to the variable
111      */
112     public void setVariableValue( String namespaceURI,
113                                   String localName,
114                                   Object value )
115     {
116         this.variables.put( new QualifiedName(namespaceURI, localName),
117                             value );
118     }
119 
120     /*** Set the value associated with a variable.
121      *
122      *  <p>
123      *  This method sets a variable that is <strong>not</strong>
124      *  associated with any particular namespace.
125      *  These variables appear such as <code>$foo</code>
126      *  in an XPath expression.
127      *  </p>
128      *
129      *  @param localName the local name of the variable
130      *  @param value the value to be bound to the variable
131      */
132     public void setVariableValue( String localName,
133                                   Object value )
134     {
135         this.variables.put( new QualifiedName(null, localName), value );
136     }
137 
138     public Object getVariableValue( String namespaceURI,
139                                     String prefix,
140                                     String localName )
141         throws UnresolvableException
142     {
143         Object key = new QualifiedName( namespaceURI, localName );
144 
145         if ( this.variables.containsKey(key) )
146         {
147             return this.variables.get( key );
148         }
149         else
150         {
151             throw new UnresolvableException( "Variable {" + namespaceURI +
152                                              "}" + prefix + ":" + localName );
153         }
154     }
155 }