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Java > Open Source Codes > org > codehaus > groovy > bsf > GroovyEngine


1 /*
2  $Id: GroovyEngine.java,v 1.10 2004/12/27 10:31:26 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 org.codehaus.groovy.bsf;
47
48 import groovy.lang.Closure;
49 import groovy.lang.GroovyShell;
50 import org.apache.bsf.BSFDeclaredBean;
51 import org.apache.bsf.BSFException;
52 import org.apache.bsf.BSFManager;
53 import org.apache.bsf.util.BSFEngineImpl;
54 import org.apache.bsf.util.BSFFunctions;
55 import org.codehaus.groovy.runtime.InvokerHelper;
56
57 import java.util.Vector JavaDoc;
58
59 /**
60  * A BSF Engine for the <a HREF="http://groovy.codehaus.org/">Groovy</a>
61  * scripting language.
62  * <p/>
63  * It's derived from the Jython / JPython engine
64  *
65  * @author James Strachan
66  */
67 public class GroovyEngine extends BSFEngineImpl {
68     private static final String JavaDoc[] EMPTY_ARGS = {
69     };
70
71     protected GroovyShell shell;
72
73     /**
74      * Convert a non java class name to a java classname
75      * This is used to convert a script name to a name
76      * that can be used as a classname with the script is
77      * loaded in GroovyClassloader#load()
78      * The method simply replaces any invalid characters
79      * with "_".
80      */
81     private String JavaDoc convertToValidJavaClassname(String JavaDoc inName) {
82         if (inName == null || inName.equals("")) {
83             return "_";
84         }
85         StringBuffer JavaDoc output = new StringBuffer JavaDoc(inName.length());
86         boolean firstChar = true;
87         for (int i = 0; i < inName.length(); ++i) {
88             char ch = inName.charAt(i);
89             if (firstChar && !Character.isJavaIdentifierStart(ch)) {
90                 ch = '_';
91             } else if (!firstChar
92                     && !(Character.isJavaIdentifierPart(ch) || ch == '.')) {
93                 ch = '_';
94             }
95             firstChar = (ch == '.');
96             output.append(ch);
97         }
98         return output.toString();
99     }
100
101     /**
102      * Allow an anonymous function to be declared and invoked
103      */
104     public Object JavaDoc apply(java.lang.String JavaDoc source,
105                         int lineNo,
106                         int columnNo,
107                         Object JavaDoc funcBody,
108                         Vector JavaDoc paramNames,
109                         Vector JavaDoc arguments)
110             throws BSFException {
111
112         Object JavaDoc object = eval(source, lineNo, columnNo, funcBody);
113         if (object instanceof Closure) {
114             // lets call the function
115
116             /** @todo we could turn the 2 vectors into a Map */
117             Closure closure = (Closure) object;
118             return closure.call(arguments.toArray());
119         }
120         return object;
121     }
122
123     /**
124      * Call the named method of the given object.
125      */
126     public Object JavaDoc call(Object JavaDoc object, String JavaDoc method, Object JavaDoc[] args) throws BSFException {
127         return InvokerHelper.invokeMethod(object, method, args);
128     }
129
130     /**
131      * Declare a bean
132      */
133     public void declareBean(BSFDeclaredBean bean) throws BSFException {
134         //System.out.println("Declaring bean: " + bean.name + " value: " + bean.bean);
135 shell.setVariable(bean.name, bean.bean);
136     }
137
138     /**
139      * Evaluate an expression.
140      */
141     public Object JavaDoc eval(String JavaDoc source, int lineNo, int columnNo, Object JavaDoc script) throws BSFException {
142         try {
143             source = convertToValidJavaClassname(source);
144             Object JavaDoc result = getEvalShell().evaluate(script.toString(), source);
145             return result;
146         } catch (Exception JavaDoc e) {
147             throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
148         }
149     }
150
151     /**
152      * Execute a script.
153      */
154     public void exec(String JavaDoc source, int lineNo, int columnNo, Object JavaDoc script) throws BSFException {
155         try {
156             // use evaluate to pass in the BSF variables
157 source = convertToValidJavaClassname(source);
158             getEvalShell().evaluate(script.toString(), source);
159             //getEvalShell().run(script.toString(), source, EMPTY_ARGS);
160 } catch (Exception JavaDoc e) {
161             throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
162         }
163     }
164
165     /**
166      * Initialize the engine.
167      */
168     public void initialize(BSFManager mgr, String JavaDoc lang, Vector JavaDoc declaredBeans) throws BSFException {
169         super.initialize(mgr, lang, declaredBeans);
170
171         // create a shell
172 shell = new GroovyShell(mgr.getClassLoader());
173
174         // register the mgr with object name "bsf"
175 shell.setVariable("bsf", new BSFFunctions(mgr, this));
176
177         int size = declaredBeans.size();
178         for (int i = 0; i < size; i++) {
179             declareBean((BSFDeclaredBean) declaredBeans.elementAt(i));
180         }
181     }
182
183     /**
184      * Undeclare a previously declared bean.
185      */
186     public void undeclareBean(BSFDeclaredBean bean) throws BSFException {
187         shell.setVariable(bean.name, null);
188     }
189
190     /**
191      * @return a newly created GroovyShell using the same variable scope but a new class loader
192      */
193     protected GroovyShell getEvalShell() {
194         return new GroovyShell(shell);
195     }
196 }
197
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