001    /*
002     $Id: GroovyEngine.java,v 1.10 2004/12/27 10:31:26 spullara 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 org.codehaus.groovy.bsf;
047    
048    import groovy.lang.Closure;
049    import groovy.lang.GroovyShell;
050    import org.apache.bsf.BSFDeclaredBean;
051    import org.apache.bsf.BSFException;
052    import org.apache.bsf.BSFManager;
053    import org.apache.bsf.util.BSFEngineImpl;
054    import org.apache.bsf.util.BSFFunctions;
055    import org.codehaus.groovy.runtime.InvokerHelper;
056    
057    import java.util.Vector;
058    
059    /**
060     * A BSF Engine for the <a href="http://groovy.codehaus.org/">Groovy</a>
061     * scripting language.
062     * <p/>
063     * It's derived from the Jython / JPython engine
064     *
065     * @author James Strachan
066     */
067    public class GroovyEngine extends BSFEngineImpl {
068        private static final String[] EMPTY_ARGS = {
069        };
070    
071        protected GroovyShell shell;
072    
073        /**
074         * Convert a non java class name to a java classname
075         * This is used to convert a script name to a name
076         * that can be used as a classname with the script is
077         * loaded in GroovyClassloader#load()
078         * The method simply replaces any invalid characters
079         * with "_".
080         */
081        private String convertToValidJavaClassname(String inName) {
082            if (inName == null || inName.equals("")) {
083                return "_";
084            }
085            StringBuffer output = new StringBuffer(inName.length());
086            boolean firstChar = true;
087            for (int i = 0; i < inName.length(); ++i) {
088                char ch = inName.charAt(i);
089                if (firstChar && !Character.isJavaIdentifierStart(ch)) {
090                    ch = '_';
091                } else if (!firstChar
092                        && !(Character.isJavaIdentifierPart(ch) || ch == '.')) {
093                    ch = '_';
094                }
095                firstChar = (ch == '.');
096                output.append(ch);
097            }
098            return output.toString();
099        }
100    
101        /**
102         * Allow an anonymous function to be declared and invoked
103         */
104        public Object apply(java.lang.String source,
105                            int lineNo,
106                            int columnNo,
107                            Object funcBody,
108                            Vector paramNames,
109                            Vector arguments)
110                throws BSFException {
111    
112            Object 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 call(Object object, String method, Object[] 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 eval(String source, int lineNo, int columnNo, Object script) throws BSFException {
142            try {
143                source = convertToValidJavaClassname(source);
144                Object result = getEvalShell().evaluate(script.toString(), source);
145                return result;
146            } catch (Exception 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 source, int lineNo, int columnNo, Object 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 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 lang, Vector 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    }