1 /*
2 * $Header$
3 * $Revision$
4 * $Date$
5 *
6 * ====================================================================
7 *
8 * Copyright 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 are
13 * met:
14 *
15 * * Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 *
18 * * Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * * Neither the name of the Jaxen Project nor the names of its
23 * contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
27 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
29 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
30 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * ====================================================================
39 * This software consists of voluntary contributions made by many
40 * individuals on behalf of the Jaxen Project and was originally
41 * created by bob mcwhirter <bob@werken.com> and
42 * James Strachan <jstrachan@apache.org>. For more information on the
43 * Jaxen Project, please see <http://www.jaxen.org/>.
44 *
45 * $Id$
46 */
47
48
49 package org.jaxen;
50
51 import java.io.Serializable;
52 import java.util.HashMap;
53 import java.util.Map;
54
55 /** Simple default implementation for <code>VariableContext</code>.
56 *
57 * <p>
58 * This is a simple table-based key-lookup implementation
59 * for <code>VariableContext</code> which can be programmatically
60 * extended by setting additional variables.
61 * </p>
62 *
63 * @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
64 */
65 public class SimpleVariableContext implements VariableContext, Serializable
66 {
67
68 private static final long serialVersionUID = 961322093794516518L;
69 /** Table of variable bindings. */
70 private Map<QualifiedName, Object> variables;
71
72 /** Construct.
73 *
74 * <p>
75 * Create a new empty variable context.
76 * </p>
77 */
78 public SimpleVariableContext()
79 {
80 variables = new HashMap<QualifiedName, Object>();
81 }
82
83 /** Set the value associated with a variable.
84 *
85 * <p>
86 * This method sets a variable that is
87 * associated with a particular namespace.
88 * These variables appear such as <code>$prefix:foo</code>
89 * in an XPath expression. Prefix to URI resolution
90 * is the responsibility of a <code>NamespaceContext</code>.
91 * Variables within a <code>VariableContext</code> are
92 * referred to purely based upon their namespace URI,
93 * if any.
94 * </p>
95 *
96 * @param namespaceURI the namespace URI of the variable
97 * @param localName the local name of the variable
98 * @param value The value to be bound to the variable
99 */
100 public void setVariableValue( String namespaceURI,
101 String localName,
102 Object value )
103 {
104 this.variables.put( new QualifiedName(namespaceURI, localName),
105 value );
106 }
107
108 /** Set the value associated with a variable.
109 *
110 * <p>
111 * This method sets a variable that is <strong>not</strong>
112 * associated with any particular namespace.
113 * These variables look like <code>$foo</code>
114 * in an XPath expression.
115 * </p>
116 *
117 * @param localName the local name of the variable
118 * @param value the value to be bound to the variable
119 */
120 public void setVariableValue( String localName,
121 Object value )
122 {
123 this.variables.put( new QualifiedName(null, localName), value );
124 }
125
126 public Object getVariableValue( String namespaceURI,
127 String prefix,
128 String localName )
129 throws UnresolvableException
130 {
131 QualifiedName key = new QualifiedName( namespaceURI, localName );
132
133 if ( this.variables.containsKey(key) )
134 {
135 return this.variables.get( key );
136 }
137 else
138 {
139 throw new UnresolvableException( "Variable " + key.getClarkForm() );
140 }
141 }
142 }