/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * 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.
 */
package org.jboss.jmx.adaptor.rmi;

import java.io.Serializable;
import java.lang.reflect.InvocationHandler;
import javax.management.ObjectName;
import javax.naming.InitialContext;


/**
 * A factory for producing MBean proxies that run on a distant node and access
 * the server through RMI. Most of the code comes from MBeanProxy.
 *
 * @version <tt>$Revision$</tt>
 * @author <a href="mailto:sacha.labourey@cogito-info.ch">Sacha Labourey</a>.
 */
public class RMIRemoteMBeanProxy 
   implements Serializable, InvocationHandler
{
   /** The server to proxy invoke calls to. */
   private final RMIAdaptor remoteServer;

   /** The name of the object to invoke. */
   private final ObjectName name;
  
   /**
    * Construct a MBeanProxy.
    */

   RMIRemoteMBeanProxy (final ObjectName name, final javax.management.MBeanServer server) throws Exception
   {
      this.name = name;
      this.remoteServer = getRmiAdaptor ();        
   }

   /** Used when args is null. */
   private static final Object EMPTY_ARGS[] = {};

   /**
    * Invoke the configured MBean via the target MBeanServer and decode
    * any resulting JMX exceptions that are thrown.
    */
   public Object invoke (final Object proxy, final java.lang.reflect.Method method, final Object[] args) throws Throwable
   {
      String methodName = method.getName();

      // Get attribute
      if (methodName.startsWith("get") && args == null)
      {
         String attrName = methodName.substring(3);
         return remoteServer.getAttribute(name, attrName);
      }

      // Is attribute
      else if (methodName.startsWith("is") && args == null)
      {
         String attrName = methodName.substring(2);
         return remoteServer.getAttribute(name, attrName);
      }

      // Set attribute
      else if (methodName.startsWith("set") && args != null && args.length == 1)
      {
         String attrName = methodName.substring(3);
         remoteServer.setAttribute(name, new javax.management.Attribute(attrName, args[0]));
         return null;         
      }

      // Operation

      // convert the parameter types to strings for JMX
      Class[] types = method.getParameterTypes();
      String[] sig = new String[types.length];
      for (int i = 0; i < types.length; i++) {
         sig[i] = types[i].getName();
      }

      // invoke the server and decode JMX exceptions
      return remoteServer.invoke(name, methodName, args == null ? EMPTY_ARGS : args, sig);
   }
   
   protected RMIAdaptor getRmiAdaptor () throws Exception
   {
      InitialContext ctx = new InitialContext();
      return (RMIAdaptor) ctx.lookup("jmx/invoker/RMIAdaptor");
   }


   ///////////////////////////////////////////////////////////////////////////
   //                          MBeanProxyInstance                           //
   ///////////////////////////////////////////////////////////////////////////

   public final ObjectName getMBeanProxyObjectName()
   {
      return name;
   }

   public final RMIAdaptor getMBeanProxyRMIAdaptor()
   {
      return remoteServer;
   }


   ///////////////////////////////////////////////////////////////////////////
   //                            Factory Methods                            //
   ///////////////////////////////////////////////////////////////////////////

   /**
    * Create an MBean proxy.
    *
    * @param intf      The interface which the proxy will implement.
    * @param name      A string used to construct the ObjectName of the
    *                  MBean to proxy to.
    * @param server    The MBeanServer that contains the MBean to proxy to.
    * @return          A MBean proxy.
    *
    * @throws Exception    Invalid object name.
    */
   public static Object create (final Class intf, final String name, final javax.management.MBeanServer server) throws Exception
   {
      return create(intf, new ObjectName(name), server);
   }    
   
   /**
    * Create an MBean proxy.
    *
    * @param intf      The interface which the proxy will implement.
    * @param name      The name of the MBean to proxy invocations to.
    * @param server    The MBeanServer that contains the MBean to proxy to.
    * @return          A MBean proxy.
    */
   public static Object create (final Class intf, final ObjectName name, final javax.management.MBeanServer server) throws Exception
   {
      return java.lang.reflect.Proxy.newProxyInstance(Thread.currentThread ().getContextClassLoader (), 
                                    new Class[] { intf },
                                    new RMIRemoteMBeanProxy(name, server));
   }
}
