001 /*
002 $Id: Binding.java,v 1.5 2005/01/05 14:46:41 glaforge Exp $
003
004 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
005
006 Redistribution and use of this software and associated documentation
007 ("Software"), with or without modification, are permitted provided
008 that the following conditions are met:
009
010 1. Redistributions of source code must retain copyright
011 statements and notices. Redistributions must also contain a
012 copy of this document.
013
014 2. Redistributions in binary form must reproduce the
015 above copyright notice, this list of conditions and the
016 following disclaimer in the documentation and/or other
017 materials provided with the distribution.
018
019 3. The name "groovy" must not be used to endorse or promote
020 products derived from this Software without prior written
021 permission of The Codehaus. For written permission,
022 please contact info@codehaus.org.
023
024 4. Products derived from this Software may not be called "groovy"
025 nor may "groovy" appear in their names without prior written
026 permission of The Codehaus. "groovy" is a registered
027 trademark of The Codehaus.
028
029 5. Due credit should be given to The Codehaus -
030 http://groovy.codehaus.org/
031
032 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
033 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
034 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
035 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
036 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
037 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
038 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
039 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
040 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
041 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
042 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
043 OF THE POSSIBILITY OF SUCH DAMAGE.
044
045 */
046 package groovy.lang;
047
048 import java.util.HashMap;
049 import java.util.Map;
050
051 /**
052 * Represents the variable bindings of a script which can be altered
053 * from outside the script object or created outside of a script and passed
054 * into it.
055 *
056 * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
057 * @version $Revision: 1.5 $
058 */
059 public class Binding extends GroovyObjectSupport {
060 private Map variables;
061
062 public Binding() {
063 variables = new HashMap();
064 }
065
066 public Binding(Map variables) {
067 this.variables = variables;
068 }
069
070 /**
071 * A helper constructor used in main(String[]) method calls
072 *
073 * @param args are the command line arguments from a main()
074 */
075 public Binding(String[] args) {
076 this();
077 setVariable("args", args);
078 }
079
080 /**
081 * @param name the name of the variable to lookup
082 * @return the variable value
083 */
084 public Object getVariable(String name) {
085 Object result = variables.get(name);
086
087 if (result == null && !variables.containsKey(name)) {
088 throw new MissingPropertyException("The property '" + name + "' is missing from the binding.",
089 name, Binding.class);
090 }
091
092 return result;
093 }
094
095 /**
096 * Sets the value of the given variable
097 * @param name the name of the variable to set
098 * @param value the new value for the given variable
099 */
100 public void setVariable(String name, Object value) {
101 variables.put(name, value);
102 }
103
104 public Map 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 getProperty(String 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 property, Object 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 }