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.apache.felix.mishell;

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)
 *
 */
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;
	}
	

}