/*

  * Copyright 2009 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.ksb.messaging;

 import java.lang.reflect.InvocationHandler;

 import java.lang.reflect.InvocationTargetException;

 import java.lang.reflect.Method;

 import java.lang.reflect.Proxy;

 import javax.xml.namespace.QName;

 import org.apache.log4j.Logger;

 import org.kuali.rice.core.api.resourceloader.GlobalResourceLoader;

 /**

  * This class creates a proxy for services deployed on KSB. A 

  * reference to the service is obtained only upon the first method

  * invocation.

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  *

  */

 public class KSBClientProxy implements InvocationHandler {

 private static final Logger LOG = Logger.getLogger(KSBClientProxy.class);

     QName serviceName;

     Object service;

     @SuppressWarnings("unchecked")

     public static <T> T newInstance(String serviceQName, Class<T> interfaceClass) throws InstantiationException, IllegalAccessException {

         return (T)Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class[] { interfaceClass }, new KSBClientProxy(serviceQName));

     }

     public KSBClientProxy(String serviceQName){

         this.serviceName = QName.valueOf(serviceQName);

     }

     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

         if (this.service == null){

             LOG.info("Getting service using GRL for: " + serviceName);

             service = GlobalResourceLoader.getService(serviceName);

             LOG.info("Obtained service using GRL for: " + serviceName);

         }

         try {

                 return method.invoke(service, args);

             } catch (InvocationTargetException e) {

                 throw e.getCause();

             }

     }

 }