/*
    * $Id: CachingGroovyEngine.java 4166 2006-10-25 07:07:33Z paulk $
    * 
    * Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
    * 
    * Redistribution and use of this software and associated documentation
    * ("Software"), with or without modification, are permitted provided that the
    * following conditions are met: 1. Redistributions of source code must retain
    * copyright statements and notices. Redistributions must also contain a copy
   * of this document. 2. Redistributions in binary form must reproduce the above
   * copyright notice, this list of conditions and the following disclaimer in
   * the documentation and/or other materials provided with the distribution. 3.
   * The name "groovy" must not be used to endorse or promote products derived
   * from this Software without prior written permission of The Codehaus. For
   * written permission, please contact info@codehaus.org. 4. Products derived
   * from this Software may not be called "groovy" nor may "groovy" appear in
   * their names without prior written permission of The Codehaus. "groovy" is a
   * registered trademark of The Codehaus. 5. Due credit should be given to The
   * Codehaus - http://groovy.codehaus.org/
   * 
   * THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR
   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
   * DAMAGE.
   *  
   */
  package org.codehaus.groovy.bsf;
  
  import groovy.lang.Binding;
  import groovy.lang.GroovyClassLoader;
  import groovy.lang.GroovyShell;
  import groovy.lang.Script;
  import org.apache.bsf.BSFDeclaredBean;
  import org.apache.bsf.BSFException;
  import org.apache.bsf.BSFManager;
  import org.apache.bsf.util.BSFFunctions;
  import org.codehaus.groovy.control.CompilerConfiguration;
  import org.codehaus.groovy.runtime.InvokerHelper;
  
  import java.io.ByteArrayInputStream;
  import java.security.AccessController;
  import java.security.PrivilegedAction;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Vector;
  import java.util.logging.Logger;
  import java.util.logging.Level;
  
  /***
   * A Caching implementation of the GroovyEngine
   *
   * @author James Birchfield
   */
  public class CachingGroovyEngine extends GroovyEngine {
      private static final Logger LOG = Logger.getLogger(CachingGroovyEngine.class.getName());
      private static final Object[] EMPTY_ARGS = new Object[]{new String[]{}};
  
      private Map evalScripts;
      private Map execScripts;
      private Binding context;
      private GroovyClassLoader loader;
  
      /***
       * Evaluate an expression.
       */
      public Object eval(String source, int lineNo, int columnNo, Object script) throws BSFException {
          try {
              Class scriptClass = (Class) evalScripts.get(script);
              if (scriptClass == null) {
                  scriptClass = loader.parseClass(new ByteArrayInputStream(script.toString().getBytes()), source);
                  evalScripts.put(script, scriptClass);
              } else {
                  LOG.fine("eval() - Using cached script...");
              }
              //can't cache the script because the context may be different.
              //but don't bother loading parsing the class again
              Script s = InvokerHelper.createScript(scriptClass, context);
              return s.run();
          } catch (Exception e) {
              throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
          }
      }
  
      /***
       * Execute a script.
       */
      public void exec(String source, int lineNo, int columnNo, Object script) throws BSFException {
          try {
              //          shell.run(script.toString(), source, EMPTY_ARGS);
  
              Class scriptClass = (Class) execScripts.get(script);
              if (scriptClass == null) {
                 scriptClass = loader.parseClass(new ByteArrayInputStream(script.toString().getBytes()), source);
                 execScripts.put(script, scriptClass);
             } else {
                 LOG.fine("exec() - Using cached version of class...");
             }
             InvokerHelper.invokeMethod(scriptClass, "main", EMPTY_ARGS);
         } catch (Exception e) {
             LOG.log(Level.WARNING, "BSF trace", e);
             throw new BSFException(BSFException.REASON_EXECUTION_ERROR, "exception from Groovy: " + e, e);
         }
     }
 
     /***
      * Initialize the engine.
      */
     public void initialize(final BSFManager mgr, String lang, Vector declaredBeans) throws BSFException {
         super.initialize(mgr, lang, declaredBeans);
         ClassLoader parent = mgr.getClassLoader();
         if (parent == null)
             parent = GroovyShell.class.getClassLoader();
         final ClassLoader finalParent = parent;
         this.loader =
                 (GroovyClassLoader) AccessController.doPrivileged(new PrivilegedAction() {
                     public Object run() {
                         CompilerConfiguration configuration = new CompilerConfiguration();
                         configuration.setClasspath(mgr.getClassPath());
                         return new GroovyClassLoader(finalParent, configuration);
                     }
                 });
         execScripts = new HashMap();
         evalScripts = new HashMap();
         context = shell.getContext();
         // create a shell
         // register the mgr with object name "bsf"
         context.setVariable("bsf", new BSFFunctions(mgr, this));
         int size = declaredBeans.size();
         for (int i = 0; i < size; i++) {
             declareBean((BSFDeclaredBean) declaredBeans.elementAt(i));
         }
     }
 }