package jade.wrapper.gateway;

//#J2ME_EXCLUDE_FILE

import jade.core.Agent;
import jade.core.behaviours.*;
import jade.util.Logger;

/**
 * This agent is the gateway able to execute all commands requests received via JadeGateway.
 * <p>
 * <code>JadeGateway</code> enables two alternative ways to implement a gateway
 * that allows non-JADE code to communicate with JADE agents.
 * <br> The first one is to extend the <code>GatewayAgent</code> 
 * <br> The second one is to extend this <code>GatewayBehaviour</code> and add an instance
 * of this Behaviour to your own agent that will have to function as a gateway (see its javadoc for reference).
 * @see JadeGateway
 * @see GatewayBehaviour
 * @author Fabio Bellifemine, Telecom Italia LAB
 * @version $Date: 2010-01-26 17:27:22 +0100 (mar, 26 gen 2010) $ $Revision: 6253 $
 **/
public class GatewayAgent extends Agent {

	private GatewayBehaviour myB = null;
	private GatewayListener listener;
	private final Logger myLogger = Logger.getMyLogger(this.getClass().getName());

	/** subclasses may implement this method.
	 * The method is called each time a request to process a command
	 * is received from the JSP Gateway.
	 * <p> The recommended pattern is the following implementation:
	 <code>
	 if (c instanceof Command1)
	 exexCommand1(c);
	 else if (c instanceof Command2)
	 exexCommand2(c);
	 </code>
	 * </p>
	 * <b> REMIND THAT WHEN THE COMMAND HAS BEEN PROCESSED,
	 * YOU MUST CALL THE METHOD <code>releaseCommand</code>.
	 * <br>Sometimes, you might prefer launching a new Behaviour that processes
	 * this command and release the command just when the Behaviour terminates,
	 * i.e. in its <code>onEnd()</code> method.
	 **/
	protected void processCommand(final Object command) {
		if (command instanceof Behaviour) {
			SequentialBehaviour sb = new SequentialBehaviour(this);
			sb.addSubBehaviour((Behaviour) command);
			sb.addSubBehaviour(new OneShotBehaviour(this) {
				public void action() {
					GatewayAgent.this.releaseCommand(command);
				}
			});
			addBehaviour(sb);
		}
		else {
			myLogger.log(Logger.WARNING, "Unknown command "+command);
		}
	}


	/**
	 * notify that the command has been processed and remove the command from the queue
	 * @param command is the same object that was passed in the processCommand method
	 **/
	final public void releaseCommand(Object command) {	
		myB.releaseCommand(command);
	}

	public GatewayAgent() {
		// enable object2agent communication with queue of infinite length
		setEnabledO2ACommunication(true, 0);
	}

	/*
	 * Those classes that extends this setup method of the GatewayAgent
	 * MUST absolutely call <code>super.setup()</code> otherwise this
	 * method is not executed and the system would not work. 
	 * @see jade.core.Agent#setup()
	 */
	protected void setup() {
		myLogger.log(Logger.INFO, "Started GatewayAgent "+getLocalName());			
		myB = new GatewayBehaviour() {
			protected void processCommand(Object command){
				((GatewayAgent)myAgent).processCommand(command);
			}
		};
		addBehaviour(myB);
		setO2AManager(myB);
		
		if (listener != null) {
			listener.handleGatewayConnected();
		}
	}
	
	protected void takeDown() {
		if (listener != null) {
			listener.handleGatewayDisconnected();
		}
	}
	
	// No need for synchronizations since this is only called when the Agent Thread has not started yet
	void setListener(GatewayListener listener) {
		this.listener = listener;
	}

}