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Java > Open Source Codes > org > jaxen > SimpleVariableContext


1 /*
2  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/SimpleVariableContext.java,v 1.13 2005/05/08 18:56:31 elharo Exp $
3  * $Revision: 1.13 $
4  * $Date: 2005/05/08 18:56:31 $
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 1.13 2005/05/08 18:56:31 elharo Exp $
60  */
61
62
63 package org.jaxen;
64
65 import java.io.Serializable JavaDoc;
66 import java.util.HashMap JavaDoc;
67 import java.util.Map JavaDoc;
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 JavaDoc
80 {
81     /** Table of variable bindings. */
82     private Map JavaDoc variables;
83
84     /** Construct.
85      *
86      * <p>
87      * Create a new empty variable context.
88      * </p>
89      */
90     public SimpleVariableContext()
91     {
92         variables = new HashMap JavaDoc();
93     }
94
95     /** Set the value associated with a variable.
96      *
97      * <p>
98      * This method sets a variable that is
99      * associated with a particular namespace.
100      * These variables appear such as <code>$prefix:foo</code>
101      * in an XPath expression. Prefix to URI resolution
102      * is the responsibility of a <code>NamespaceContext</code>.
103      * Variables within a <code>VariableContext</code> are
104      * referred to purely based upon their namespace URI,
105      * if any.
106      * </p>
107      *
108      * @param namespaceURI the namespace URI of the variable
109      * @param localName the local name of the variable
110      * @param value The value to be bound to the variable
111      */
112     public void setVariableValue( String JavaDoc namespaceURI,
113                                   String JavaDoc localName,
114                                   Object JavaDoc value )
115     {
116         this.variables.put( new QualifiedName(namespaceURI, localName),
117                             value );
118     }
119
120     /** Set the value associated with a variable.
121      *
122      * <p>
123      * This method sets a variable that is <strong>not</strong>
124      * associated with any particular namespace.
125      * These variables look like <code>$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 JavaDoc localName,
133                                   Object JavaDoc value )
134     {
135         this.variables.put( new QualifiedName(null, localName), value );
136     }
137
138     public Object JavaDoc getVariableValue( String JavaDoc namespaceURI,
139                                     String JavaDoc prefix,
140                                     String JavaDoc localName )
141         throws UnresolvableException
142     {
143         Object JavaDoc 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 }
156
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