OSGiScriptEngineFactory.java

/*
 *   Copyright 2005 The Apache Software Foundation
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 *
 */
package org.jclouds.karaf.commands.table.internal.osgi;

import java.util.List;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;

/**
 * This is a wrapper class for the ScriptEngineFactory class that deals with
 * context class loader issues It is necessary because engines (at least ruby)
 * use the context classloader to find their resources (i.e., their "native"
 * classes)
 */

// modified version of http://svn.apache.org/repos/asf/felix/trunk/mishell/src/main/java/org/apache/felix/mishell/OSGiScriptEngineFactory.java
public class OSGiScriptEngineFactory implements ScriptEngineFactory {
   private ScriptEngineFactory factory;
   private ClassLoader contextClassLoader;

   public OSGiScriptEngineFactory(ScriptEngineFactory factory,
         ClassLoader contextClassLoader) {
      this.factory = factory;
      this.contextClassLoader = contextClassLoader;
   }

   public String getEngineName() {
      return factory.getEngineName();
   }

   public String getEngineVersion() {
      return factory.getEngineVersion();
   }

   public List<String> getExtensions() {
      return factory.getExtensions();
   }

   public String getLanguageName() {
      return factory.getLanguageName();
   }

   public String getLanguageVersion() {
      return factory.getLanguageVersion();
   }

   public String getMethodCallSyntax(String obj, String m, String... args) {
      return factory.getMethodCallSyntax(obj, m, args);
   }

   public List<String> getMimeTypes() {
      return factory.getMimeTypes();
   }

   public List<String> getNames() {
      return factory.getNames();
   }

   public String getOutputStatement(String toDisplay) {
      return factory.getOutputStatement(toDisplay);
   }

   public Object getParameter(String key) {
      return factory.getParameter(key);
   }

   public String getProgram(String... statements) {
      return factory.getProgram(statements);
   }

   public ScriptEngine getScriptEngine() {
      ScriptEngine engine = null;
      if (contextClassLoader != null) {
         ClassLoader old = Thread.currentThread().getContextClassLoader();
         Thread.currentThread().setContextClassLoader(contextClassLoader);
         engine = factory.getScriptEngine();
         Thread.currentThread().setContextClassLoader(old);
      } else
         engine = factory.getScriptEngine();
      return engine;
   }

}