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Java > Open Source Codes > groovy > lang > Script


1 /*
2  $Id: Script.java,v 1.18 2004/12/27 10:31:24 spullara 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 org.codehaus.groovy.ast.expr.ArgumentListExpression;
49 import org.codehaus.groovy.control.CompilationFailedException;
50 import org.codehaus.groovy.runtime.InvokerHelper;
51
52 import java.io.File JavaDoc;
53 import java.io.IOException JavaDoc;
54
55 /**
56  * This object represents a Groovy script
57  *
58  * @author <a HREF="mailto:james@coredevelopers.net">James Strachan</a>
59  * @author Guillaume Laforge
60  * @version $Revision: 1.18 $
61  */
62 public abstract class Script extends GroovyObjectSupport {
63     private Binding binding = new Binding();
64
65     protected Script() {
66     }
67
68     protected Script(Binding binding) {
69         this.binding = binding;
70     }
71
72     public Binding getBinding() {
73         return binding;
74     }
75
76     public void setBinding(Binding binding) {
77         this.binding = binding;
78     }
79
80     public Object JavaDoc getProperty(String JavaDoc property) {
81         //System.out.println("Script.getProperty for: " + property + " with binding: " + binding.getVariables());
82 try {
83             return binding.getVariable(property);
84         } catch (MissingPropertyException e) {
85             return super.getProperty(property);
86         }
87     }
88
89     public void setProperty(String JavaDoc property, Object JavaDoc newValue) {
90         //System.out.println("Script.setProperty for: " + property + " with newValue: " + newValue);
91 binding.setVariable(property, newValue);
92         //System.out.println("binding are now: " + binding.getVariables());
93 }
94
95     /**
96      * Invoke a method (or closure in the binding) defined.
97      *
98      * @param name method to call
99      * @param args arguments to pass to the method
100      * @return value
101      */
102     public Object JavaDoc invokeMethod(String JavaDoc name, Object JavaDoc args) {
103         try {
104             return super.invokeMethod(name, args);
105         }
106                 // if the method was not found in the current scope (the script's methods)
107 // let's try to see if there's a method closure with the same name in the binding
108 catch (MissingMethodException mme) {
109             try {
110                 if (name.equals(mme.getMethod())) {
111                     Object JavaDoc boundClosure = binding.getVariable(name);
112                     if (boundClosure != null && boundClosure instanceof Closure) {
113                         return ((Closure) boundClosure).call(args);
114                     } else {
115                         throw mme;
116                     }
117                 } else {
118                     throw mme;
119                 }
120             } catch (MissingPropertyException mpe) {
121                 throw mme;
122             }
123         }
124     }
125
126     /**
127      * The main instance method of a script which has variables in scope
128      * as defined by the current {@link Binding} instance.
129      *
130      * @return
131      */
132     public abstract Object JavaDoc run();
133
134     // println helper methods
135
136     /**
137      * Prints a newline to the current 'out' variable which should be a PrintWriter
138      * or at least have a println() method defined on it.
139      * If there is no 'out' property then print to standard out.
140      */
141     public void println() {
142         Object JavaDoc object;
143
144         try {
145             object = getProperty("out");
146         } catch (MissingPropertyException e) {
147             System.out.println();
148             return;
149         }
150
151         InvokerHelper.invokeMethod(object, "println", ArgumentListExpression.EMPTY_ARRAY);
152     }
153
154     /**
155      * Prints the value to the current 'out' variable which should be a PrintWriter
156      * or at least have a print() method defined on it.
157      * If there is no 'out' property then print to standard out.
158      */
159     public void print(Object JavaDoc value) {
160         Object JavaDoc object;
161
162         try {
163             object = getProperty("out");
164         } catch (MissingPropertyException e) {
165             System.out.print(value);
166             return;
167         }
168
169         InvokerHelper.invokeMethod(object, "print", new Object JavaDoc[]{value});
170     }
171
172     /**
173      * Prints the value and a newline to the current 'out' variable which should be a PrintWriter
174      * or at least have a println() method defined on it.
175      * If there is no 'out' property then print to standard out.
176      */
177     public void println(Object JavaDoc value) {
178         Object JavaDoc object;
179
180         try {
181             object = getProperty("out");
182         } catch (MissingPropertyException e) {
183             System.out.println(value);
184             return;
185         }
186
187         InvokerHelper.invokeMethod(object, "println", new Object JavaDoc[]{value});
188     }
189
190     /**
191      * A helper method to allow the dynamic evaluation of groovy expressions using this
192      * scripts binding as the variable scope
193      *
194      * @param expression is the Groovy script expression to evaluate
195      */
196     public Object JavaDoc evaluate(String JavaDoc expression) throws CompilationFailedException, IOException JavaDoc {
197         GroovyShell shell = new GroovyShell(binding);
198         return shell.evaluate(expression);
199     }
200
201     /**
202      * A helper method to allow the dynamic evaluation of groovy expressions using this
203      * scripts binding as the variable scope
204      *
205      * @param file is the Groovy script to evaluate
206      */
207     public Object JavaDoc evaluate(File JavaDoc file) throws CompilationFailedException, IOException JavaDoc {
208         GroovyShell shell = new GroovyShell(binding);
209         return shell.evaluate(file);
210     }
211
212     /**
213      * A helper method to allow scripts to be run taking command line arguments
214      */
215     public void run(File JavaDoc file, String JavaDoc[] arguments) throws CompilationFailedException, IOException JavaDoc {
216         GroovyShell shell = new GroovyShell(binding);
217         shell.run(file, arguments);
218     }
219 }
220
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