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1   /*
2    $Id: Script.java,v 1.13 2004/05/15 04:48:29 bran 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.io.File;
49  import java.io.IOException;
50  
51  import org.codehaus.groovy.ast.expr.ArgumentListExpression;
52  import org.codehaus.groovy.control.CompilationFailedException;
53  import org.codehaus.groovy.runtime.InvokerHelper;
54  
55  /***
56   * This object represents a Groovy script
57   * 
58   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
59   * @version $Revision: 1.13 $
60   */
61  public abstract class Script extends GroovyObjectSupport {
62      private Binding binding = new Binding();
63  
64      protected Script() {
65      }
66  
67      protected Script(Binding binding) {
68          this.binding = binding;
69      }
70  
71      public Binding getBinding() {
72          return binding;
73      }
74  
75      public void setBinding(Binding binding) {
76          this.binding = binding;
77      }
78  
79      public Object getProperty(String property) {
80          //System.out.println("Script.getProperty for: " + property + " with binding: " + binding.getVariables());
81          Object answer = binding.getVariable(property);
82          if (answer == null) {
83              try {
84                  return super.getProperty(property);
85              }
86              catch (MissingPropertyException e) {
87                  // ignore errors inside scripts
88              }
89          }
90          return answer;
91      }
92  
93      public void setProperty(String property, Object newValue) {
94          //System.out.println("Script.setProperty for: " + property + " with newValue: " + newValue);
95          binding.setVariable(property, newValue);
96          //System.out.println("binding are now: " + binding.getVariables());
97      }
98  
99      /***
100      * The main instance method of a script which has variables in scope
101      * as defined by the current {@link Binding} instance.
102      * 
103      * @return
104      */
105     public abstract Object run();
106 
107     // println helper methods
108 
109     /***
110      * Prints a newline to the current 'out' variable which should be a PrintWriter
111      * or at least have a println() method defined on it.
112      * If there is no 'out' property then print to standard out.
113      */
114     public void println() {
115         Object object = getProperty("out");
116         if (object != null) {
117             InvokerHelper.invokeMethod(object, "println", ArgumentListExpression.EMPTY_ARRAY);
118         }
119         else {
120             System.out.println();
121         }
122     }
123 
124     /***
125      * Prints the value to the current 'out' variable which should be a PrintWriter
126      * or at least have a print() method defined on it. 
127      * If there is no 'out' property then print to standard out.
128      */
129     public void print(Object value) {
130         Object object = getProperty("out");
131         if (object != null) {
132             InvokerHelper.invokeMethod(object, "print", new Object[] { value });
133         }
134         else {
135             System.out.print(value);
136         }
137     }
138 
139     /***
140      * Prints the value and a newline to the current 'out' variable which should be a PrintWriter
141      * or at least have a println() method defined on it. 
142      * If there is no 'out' property then print to standard out.
143      */
144     public void println(Object value) {
145         Object object = getProperty("out");
146         if (object != null) {
147             InvokerHelper.invokeMethod(object, "println", new Object[] { value });
148         }
149         else {
150             System.out.println(value);
151         }
152     }
153     
154     /***
155      * A helper method to allow the dynamic evaluation of groovy expressions using this
156      * scripts binding as the variable scope
157      * 
158      * @param expression is the Groovy script expression to evaluate
159      */
160     public Object evaluate(String expression) throws CompilationFailedException, IOException {
161         GroovyShell shell = new GroovyShell(binding);
162         return shell.evaluate(expression);
163     }
164     
165     /***
166      * A helper method to allow the dynamic evaluation of groovy expressions using this
167      * scripts binding as the variable scope
168      * 
169      * @param file is the Groovy script to evaluate
170      */
171     public Object evaluate(File file) throws CompilationFailedException, IOException {
172         GroovyShell shell = new GroovyShell(binding);
173         return shell.evaluate(file);
174     }
175     
176     /***
177      * A helper method to allow scripts to be run taking command line arguments
178      */
179     public void run(File file, String[] arguments) throws CompilationFailedException, IOException {
180         GroovyShell shell = new GroovyShell(binding);
181         shell.run(file, arguments);
182     }
183 }