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1   /*
2    $Id: GroovyEngine.java,v 1.8 2004/05/17 22:27:11 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 org.codehaus.groovy.bsf;
47  
48  import groovy.lang.Closure;
49  import groovy.lang.GroovyShell;
50  
51  import java.util.Vector;
52  
53  import org.apache.bsf.BSFDeclaredBean;
54  import org.apache.bsf.BSFException;
55  import org.apache.bsf.BSFManager;
56  import org.apache.bsf.util.BSFEngineImpl;
57  import org.apache.bsf.util.BSFFunctions;
58  import org.codehaus.groovy.runtime.InvokerHelper;
59  
60  /***
61   * A BSF Engine for the <a href="http://groovy.codehaus.org/">Groovy</a> 
62   * scripting language.
63   * 
64   * It's derived from the Jython / JPython engine
65   *
66   * @author James Strachan
67   */
68  public class GroovyEngine extends BSFEngineImpl {
69      private static final String[] EMPTY_ARGS = {
70      };
71  
72      protected GroovyShell shell;
73  
74      /***
75       * Convert a non java class name to a java classname
76       * This is used to convert a script name to a name
77       * that can be used as a classname with the script is
78       * loaded in GroovyClassloader#load()
79       * The method simply replaces any invalid characters
80       * with "_".
81       */
82      private String convertToValidJavaClassname(String inName) {
83          if (inName == null || inName == "") {
84              return "_";
85          }
86          StringBuffer output = new StringBuffer(inName.length());
87          boolean firstChar = true;
88          for (int i = 0; i < inName.length(); ++i) {
89              char ch = inName.charAt(i);
90              if (firstChar && !Character.isJavaIdentifierStart(ch)) {
91                  ch = '_';
92              } else if (!firstChar
93                         && !(Character.isJavaIdentifierPart(ch) || ch == '.')) {
94                  ch = '_';
95              }
96              firstChar = (ch == '.');
97              output.append(ch);
98          }
99          return output.toString();
100     }
101     
102     /***
103      * Allow an anonymous function to be declared and invoked
104      */
105     public Object apply(
106         java.lang.String source,
107         int lineNo,
108         int columnNo,
109         Object funcBody,
110         Vector paramNames,
111         Vector arguments)
112         throws BSFException {
113         
114         Object object = eval(source, lineNo, columnNo, funcBody);
115         if (object instanceof Closure) {
116             // lets call the function
117 
118             /*** @todo we could turn the 2 vectors into a Map */
119             Closure closure = (Closure) object;
120             return closure.call(arguments.toArray());
121         }
122         return object;
123     }
124 
125     /***
126      * Call the named method of the given object.
127      */
128     public Object call(Object object, String method, Object[] args) throws BSFException {
129         return InvokerHelper.invokeMethod(object, method, args);
130     }
131 
132     /***
133      * Declare a bean
134      */
135     public void declareBean(BSFDeclaredBean bean) throws BSFException {
136         //System.out.println("Declaring bean: " + bean.name + " value: " + bean.bean);
137         shell.setVariable(bean.name, bean.bean);
138     }
139 
140     /***
141      * Evaluate an expression.
142      */
143     public Object eval(String source, int lineNo, int columnNo, Object script) throws BSFException {
144         try {
145             source = convertToValidJavaClassname(source);
146             Object result = getEvalShell().evaluate(script.toString(), source);
147             return result;
148         }
149         catch (Exception e) {
150             e.printStackTrace();
151             throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
152         }
153     }
154 
155     /***
156      * Execute a script. 
157      */
158     public void exec(String source, int lineNo, int columnNo, Object script) throws BSFException {
159         try {
160             // use evaluate to pass in the BSF variables
161             source = convertToValidJavaClassname(source);
162             getEvalShell().evaluate(script.toString(), source);
163             //getEvalShell().run(script.toString(), source, EMPTY_ARGS);
164         }
165         catch (Exception e) {
166             e.printStackTrace();
167             throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
168         }
169     }
170 
171     /***
172      * Initialize the engine.
173      */
174     public void initialize(BSFManager mgr, String lang, Vector declaredBeans) throws BSFException {
175         super.initialize(mgr, lang, declaredBeans);
176 
177         // create a shell
178         shell = new GroovyShell(mgr.getClassLoader());
179 
180         // register the mgr with object name "bsf"
181         shell.setVariable("bsf", new BSFFunctions(mgr, this));
182 
183         int size = declaredBeans.size();
184         for (int i = 0; i < size; i++) {
185             declareBean((BSFDeclaredBean) declaredBeans.elementAt(i));
186         }
187     }
188 
189     /***
190      * Undeclare a previously declared bean.
191      */
192     public void undeclareBean(BSFDeclaredBean bean) throws BSFException {
193         shell.setVariable(bean.name, null);
194     }
195 
196     /***
197      * @return a newly created GroovyShell using the same variable scope but a new class loader
198      */
199     protected GroovyShell getEvalShell() {
200         return new GroovyShell(shell);
201     }
202 }