TestUsingProxy.java

/*
 * Copyright (C) 2011 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
 * @author <a href="hoang281283@gmail.com">Minh Hoang TO</a>
 * @date 7/8/11
 */
public class TestUsingProxy
{

   public interface Foo
   {
      public void bar();
   }

   public class Decorator implements Foo
   {
      private Foo decoratedObject;

      public Decorator(Foo foo)
      {
         this.decoratedObject = foo;
      }

      public void bar()
      {
         System.out.println("Calling bar() from Decorator");
         decoratedObject.bar();
      }
   }

   public class CustomDecorator extends Decorator
   {
      public CustomDecorator(Foo foo)
      {
         super(foo);
      }

      public void bar()
      {
         System.out.println("Calling bar() from CustomDecorator");
         super.bar();
      }
   }

   public static void main(String[] args) throws Exception
   {
      InvocationHandler handler = new InvocationHandler()
      {
         public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
         {
            System.out.println("Executing the handler method why invoking method: " + method.getName() + " on proxy");
            return null;
         }
      };

      Class<? extends Proxy> proxyClazzForFoo = Proxy.getProxyClass(Thread.currentThread().getContextClassLoader(), Foo.class).asSubclass(Proxy.class);

      Foo fooCreatedByProxy = (Foo)proxyClazzForFoo.getConstructor(InvocationHandler.class).newInstance(handler);

      TestUsingProxy test = new TestUsingProxy();
      test.new CustomDecorator(test.new Decorator(fooCreatedByProxy)).bar();
   }

}