packetscheduler.java

Bluetooth chat Server and Client in j2me

/*
 The Bluetooth Library for client-server communication
 Copyright (C) 2006 Martin Vysny

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.

 This program 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 General Public License for more details.
 */
package net.sf.btw.btlib;

import java.util.Enumeration;
import java.util.Hashtable;

import javax.bluetooth.L2CAPConnection;

/**
 * The packet scheduler.
 * 
 * @author Martin Vysny
 * 
 */
final class PacketScheduler {
	/**
	 * Creates new scheduler.
	 * 
	 * @param listener
	 *            the error listener.
	 */
	PacketScheduler(final IErrorListener listener) {
		super();
		this.listener = listener;
	}

	final IErrorListener listener;

	/**
	 * Maps ID to the {@link PacketQueueSender} instance.
	 */
	private final Hashtable table = new Hashtable();

	/**
	 * Adds route for the client.
	 * 
	 * @param id
	 *            the client id.
	 * @param connection
	 *            the connection to the client
	 */
	void addRoute(final Byte id, final L2CAPConnection connection) {
		synchronized (table) {
			final PacketQueueSender thread = new PacketQueueSender(this, id
					.byteValue(), connection);
			final PacketQueueSender oldThread = (PacketQueueSender) table.put(
					id, thread);
			if (oldThread != null)
				oldThread.interrupt();
			thread.start();
		}
	}

	/**
	 * Removes route for the client.
	 * 
	 * @param id
	 *            the client id.
	 */
	void removeRoute(final Byte id) {
		synchronized (table) {
			final PacketQueueSender oldThread = (PacketQueueSender) table
					.remove(id);
			if (oldThread != null)
				oldThread.interrupt();
		}
	}

	/**
	 * Sends given packet to the destination.
	 * 
	 * @param targetId
	 *            target id to send the packet to.
	 * @param packet
	 *            packet to send.
	 */
	void sendPacket(final Byte targetId, byte[] packet) {
		synchronized (table) {
			final PacketQueueSender oldThread = (PacketQueueSender) table
					.get(targetId);
			oldThread.addPacket(packet);
		}
	}

	/**
	 * Stops the scheduler, kills all threads etc.
	 */
	void stop() {
		synchronized (table) {
			for (final Enumeration e = table.elements(); e.hasMoreElements();) {
				final PacketQueueSender oldThread = (PacketQueueSender) e
						.nextElement();
				oldThread.interrupt();
			}
			table.clear();
		}
	}

}