NodeLEAP.java

/*****************************************************************
JADE - Java Agent DEvelopment Framework is a framework to develop 
multi-agent systems in compliance with the FIPA specifications.
Copyright (C) 2000 CSELT S.p.A. 

GNU Lesser General Public License

This library 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, 
version 2.1 of the License. 

This library 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 library; if not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA  02111-1307, USA.
 *****************************************************************/

package jade.imtp.leap;

//#MIDP_EXCLUDE_BEGIN
import java.io.ObjectStreamException;
//#MIDP_EXCLUDE_END

import jade.core.BaseNode;
import jade.core.HorizontalCommand;
import jade.core.IMTPException;
import jade.core.ServiceException;
import jade.util.Logger;


/**
   This class implements a platform node accessible by means of the LEAP IMTP 
   @author Giovanni Rimassa - FRAMeTech s.r.l
   @author Giovanni Caire - TILAB
 */
class NodeLEAP extends BaseNode {
	// This monitor is used to hang a remote ping() call in order to
	// detect node failures.
	private Object terminationLock = new Object();
	private boolean terminating = false;
	private CommandDispatcher myDispatcher;
	private Logger myLogger = Logger.getMyLogger(getClass().getName());

	public NodeLEAP(String name, boolean hasPM, CommandDispatcher dispatcher) {
		super(name, hasPM);
		this.myDispatcher = dispatcher;
	}

	public Object accept(HorizontalCommand cmd) throws IMTPException {
		try {
			if(terminating) {
				throw new IMTPException("Dead node");
			}
			return serveHorizontalCommand(cmd);
		}
		catch(ServiceException se) {
			throw new IMTPException("Service Error", se);
		}
	}

	public boolean ping(boolean hang) throws IMTPException {
		if(hang) {
			waitTermination();
		}
		myLogger.log(Logger.CONFIG, "Node "+getName()+" terminated ("+terminating+")");
		return terminating;
	}

	public void exit() throws IMTPException {
		myLogger.log(Logger.CONFIG, "Node "+getName()+" exiting...");
		// Unblock threads hung in ping() method (this will deregister the container)
		terminating = true;
		notifyTermination();
	}

	public void interrupt() throws IMTPException {
		notifyTermination();
	}


	private void waitTermination() {
		synchronized(terminationLock) {
			try {
				terminationLock.wait();
			}
			catch(InterruptedException ie) {
				System.out.println("PING wait interrupted");
				// Do nothing
			}
		}
	}

	private void notifyTermination() {
		synchronized(terminationLock) {
			terminationLock.notifyAll();
		}
	}
	
	//#MIDP_EXCLUDE_BEGIN
	//////////////////////////////////////////////////////////////////////////////////////////
	// LEAP nodes are serialized by means of the DeliverableDataOutput/InputStream classes.
	// However we also implements the node<-->stub substitution standard methods
	// to achieve the same result in case one serializes them using Java Serialization
	//////////////////////////////////////////////////////////////////////////////////////////
	private Object writeReplace() throws ObjectStreamException {
		try {
			NodeStub stub = (NodeStub) myDispatcher.buildLocalStub(this);
			stub.setName(getName());
			stub.setPlatformManager(hasPlatformManager());
			return stub;
		}
		catch (IMTPException imtpe) {
			throw new NodeStubAccessException("Can't retrieve NodeStub. "+imtpe.getMessage());
		}
	}
	
	private static class NodeStubAccessException extends ObjectStreamException {
		public NodeStubAccessException(String message) {
			super(message);
		}
	}
	//#MIDP_EXCLUDE_END
}