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    1   /*
    2    $Id: GroovyEngine.java 4166 2006-10-25 07:07:33Z paulk $
    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;
    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      protected GroovyShell shell;
    69
    70      /*
    71       * Convert a non java class name to a java classname
    72       * This is used to convert a script name to a name
    73       * that can be used as a classname with the script is
    74       * loaded in GroovyClassloader#load()
    75       * The method simply replaces any invalid characters
    76       * with "_".
    77       */
    78      private String convertToValidJavaClassname(String inName) {
    79          if (inName == null || inName.equals("")) {
    80              return "_";
    81          }
    82          StringBuffer output = new StringBuffer(inName.length());
    83          boolean firstChar = true;
    84          for (int i = 0; i < inName.length(); ++i) {
    85              char ch = inName.charAt(i);
    86              if (firstChar && !Character.isJavaIdentifierStart(ch)) {
    87                  ch = '_';
    88              } else if (!firstChar
    89                      && !(Character.isJavaIdentifierPart(ch) || ch == '.')) {
    90                  ch = '_';
    91              }
    92              firstChar = (ch == '.');
    93              output.append(ch);
    94          }
    95          return output.toString();
    96      }
    97
    98      /***
    99       * Allow an anonymous function to be declared and invoked
    100      */
    101     public Object apply(String source, int lineNo, int columnNo, Object funcBody, Vector paramNames,
    102                         Vector arguments) throws BSFException {
    103         Object object = eval(source, lineNo, columnNo, funcBody);
    104         if (object instanceof Closure) {
    105             // lets call the function
    106             Closure closure = (Closure) object;
    107             return closure.call(arguments.toArray());
    108         }
    109         return object;
    110     }
    111
    112     /***
    113      * Call the named method of the given object.
    114      */
    115     public Object call(Object object, String method, Object[] args) throws BSFException {
    116         return InvokerHelper.invokeMethod(object, method, args);
    117     }
    118
    119     /***
    120      * Evaluate an expression.
    121      */
    122     public Object eval(String source, int lineNo, int columnNo, Object script) throws BSFException {
    123         try {
    124             source = convertToValidJavaClassname(source);
    125             return getEvalShell().evaluate(script.toString(), source);
    126         } catch (Exception e) {
    127             throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
    128         }
    129     }
    130
    131     /***
    132      * Execute a script.
    133      */
    134     public void exec(String source, int lineNo, int columnNo, Object script) throws BSFException {
    135         try {
    136             // use evaluate to pass in the BSF variables
    137             source = convertToValidJavaClassname(source);
    138             getEvalShell().evaluate(script.toString(), source);
    139         } catch (Exception e) {
    140             throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
    141         }
    142     }
    143
    144     /***
    145      * Initialize the engine.
    146      */
    147     public void initialize(BSFManager mgr, String lang, Vector declaredBeans) throws BSFException {
    148         super.initialize(mgr, lang, declaredBeans);
    149
    150         // create a shell
    151         shell = new GroovyShell(mgr.getClassLoader());
    152
    153         // register the mgr with object name "bsf"
    154         shell.setVariable("bsf", new BSFFunctions(mgr, this));
    155
    156         int size = declaredBeans.size();
    157         for (int i = 0; i < size; i++) {
    158             declareBean((BSFDeclaredBean) declaredBeans.elementAt(i));
    159         }
    160     }
    161
    162     /***
    163      * Declare a bean
    164      */
    165     public void declareBean(BSFDeclaredBean bean) throws BSFException {
    166         shell.setVariable(bean.name, bean.bean);
    167     }
    168
    169     /***
    170      * Undeclare a previously declared bean.
    171      */
    172     public void undeclareBean(BSFDeclaredBean bean) throws BSFException {
    173         shell.setVariable(bean.name, null);
    174     }
    175
    176     /***
    177      * @return a newly created GroovyShell using the same variable scope but a new class loader
    178      */
    179     protected GroovyShell getEvalShell() {
    180         return new GroovyShell(shell);
    181     }
    182 }