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Java > Open Source Codes > groovy > lang > Binding


1 /*
2  $Id: Binding.java,v 1.5 2005/01/05 14:46:41 glaforge Exp $
3
4  Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
5
6  Redistribution and use of this software and associated documentation
7  ("Software"), with or without modification, are permitted provided
8  that the following conditions are met:
9
10  1. Redistributions of source code must retain copyright
11     statements and notices. Redistributions must also contain a
12     copy of this document.
13
14  2. Redistributions in binary form must reproduce the
15     above copyright notice, this list of conditions and the
16     following disclaimer in the documentation and/or other
17     materials provided with the distribution.
18
19  3. The name "groovy" must not be used to endorse or promote
20     products derived from this Software without prior written
21     permission of The Codehaus. For written permission,
22     please contact info@codehaus.org.
23
24  4. Products derived from this Software may not be called "groovy"
25     nor may "groovy" appear in their names without prior written
26     permission of The Codehaus. "groovy" is a registered
27     trademark of The Codehaus.
28
29  5. Due credit should be given to The Codehaus -
30     http://groovy.codehaus.org/
31
32  THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
33  ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
34  NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
35  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
36  THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
39  SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43  OF THE POSSIBILITY OF SUCH DAMAGE.
44
45  */
46 package groovy.lang;
47
48 import java.util.HashMap JavaDoc;
49 import java.util.Map JavaDoc;
50
51 /**
52  * Represents the variable bindings of a script which can be altered
53  * from outside the script object or created outside of a script and passed
54  * into it.
55  *
56  * @author <a HREF="mailto:james@coredevelopers.net">James Strachan</a>
57  * @version $Revision: 1.5 $
58  */
59 public class Binding extends GroovyObjectSupport {
60     private Map JavaDoc variables;
61     
62     public Binding() {
63         variables = new HashMap JavaDoc();
64     }
65     
66     public Binding(Map JavaDoc variables) {
67         this.variables = variables;
68     }
69     
70     /**
71      * A helper constructor used in main(String[]) method calls
72      *
73      * @param args are the command line arguments from a main()
74      */
75     public Binding(String JavaDoc[] args) {
76         this();
77         setVariable("args", args);
78     }
79     
80     /**
81      * @param name the name of the variable to lookup
82      * @return the variable value
83      */
84     public Object JavaDoc getVariable(String JavaDoc name) {
85         Object JavaDoc result = variables.get(name);
86         
87         if (result == null && !variables.containsKey(name)) {
88             throw new MissingPropertyException("The property '" + name + "' is missing from the binding.",
89                                                name, Binding.class);
90         }
91         
92         return result;
93     }
94     
95     /**
96      * Sets the value of the given variable
97      * @param name the name of the variable to set
98      * @param value the new value for the given variable
99      */
100     public void setVariable(String JavaDoc name, Object JavaDoc value) {
101         variables.put(name, value);
102     }
103     
104     public Map JavaDoc getVariables() {
105         return variables;
106     }
107
108     /**
109      * Overloaded to make variables appear as bean properties or via the subscript operator
110      */
111     public Object JavaDoc getProperty(String JavaDoc property) {
112         /** @todo we should check if we have the property with the metaClass instead of try/catch */
113         try {
114             return super.getProperty(property);
115         }
116         catch (MissingPropertyException e) {
117             return getVariable(property);
118         }
119     }
120
121     /**
122      * Overloaded to make variables appear as bean properties or via the subscript operator
123      */
124     public void setProperty(String JavaDoc property, Object JavaDoc newValue) {
125         /** @todo we should check if we have the property with the metaClass instead of try/catch */
126         try {
127             super.setProperty(property, newValue);
128         }
129         catch (MissingPropertyException e) {
130             setVariable(property, newValue);
131         }
132     }
133
134 }
135
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