receiver.java

tinyos-2.0源代码！转载而已！要的尽管拿！

// $Id: Receiver.java,v 1.1.2.2 2006/02/16 01:21:25 idgay Exp $

/*									tab:4
 * "Copyright (c) 2000-2003 The Regents of the University  of California.  
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice, the following
 * two paragraphs and the author appear in all copies of this software.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS."
 *
 * Copyright (c) 2002-2003 Intel Corporation
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE     
 * file. If you do not find these files, copies can be found by writing to
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA, 
 * 94704.  Attention:  Intel License Inquiry.
 */
/* Authors:  David Gay  <[e-mail]>
 *           Intel Research Berkeley Lab
 *
 */

/**
 * @author David Gay <[e-mail]>
 * @author Intel Research Berkeley Lab
 */

package net.tinyos.message;

import net.tinyos.util.*;
import net.tinyos.packet.*;
import java.util.*;
import java.io.*;

/**
 * Receiver class (receive tinyos messages).
 *
 * A receiver class provides a simple interface built on Message for
 * receiving tinyos messages from a SerialForwarder
 *
 * @version	1, 15 Jul 2002
 * @author	David Gay
 */
public class Receiver implements PacketListenerIF {
    public static final boolean DEBUG = false;
    public static final boolean DISPLAY_ERROR_MSGS = true;

    Hashtable templateTbl; // Mapping from AM type to msgTemplate
    PhoenixSource source;
    /**
     * Inner class representing a single MessageListener and its
     * associated Message template.
     */
    class msgTemplate {
	Message template;
	MessageListener listener;
	msgTemplate(Message template, MessageListener listener) {
	    this.template = template;
	    this.listener = listener;
	}

	public boolean equals(Object o) {
	    try {
		msgTemplate mt = (msgTemplate)o;
		if (mt.template.getClass().equals(this.template.getClass()) &&
		    mt.listener.equals(this.listener)) {
		    return true;
		}
	    } catch (Exception e) {
		return false;
	    }
	    return false;
	}

	public int hashCode() {
	    return listener.hashCode();
	}
    }

    /**
     * Create a receiver messages from forwarder of any group id and
     * of active message type m.getType()
     * When such a message is received, a new instance of m's class is
     * created with the received data and send to listener.messageReceived
     * @param forwarder packet source to listen to
     */
    public Receiver(PhoenixSource forwarder) {
	this.templateTbl = new Hashtable();
	this.source = forwarder;
	forwarder.registerPacketListener(this);
    }

    /**
     * Register a particular listener for a particular message type.
     * More than one listener can be registered for each message type.
     * @param m specify message type and template we're listening for
     * @param listener destination for received messages
     */
    public void registerListener(Message template, MessageListener listener) {
	Integer amType = new Integer(template.amType());
	Vector vec = (Vector)templateTbl.get(amType);
	if (vec == null) {
	    vec = new Vector();
	}
	vec.addElement(new msgTemplate(template, listener));
	templateTbl.put(amType, vec);
    }

    /**
     * Stop listening for messages of the given type with the given listener.
     * @param m specify message type and template we're listening for
     * @param listener destination for received messages
     */
    public void deregisterListener(Message template, MessageListener listener) {
	Integer amType = new Integer(template.amType());
	Vector vec = (Vector)templateTbl.get(amType);
	if (vec == null) {
	    throw new IllegalArgumentException("No listeners registered for message type "+template.getClass().getName()+" (AM type "+template.amType()+")");
	}
	msgTemplate mt = new msgTemplate(template, listener);
	// Remove all occurrences
	while (vec.removeElement(mt)) ;
	if (vec.size() == 0) templateTbl.remove(amType);
    }

    private void error(msgTemplate temp, String msg) {
	System.err.println("receive error for " + temp.template.getClass().getName() +
			   " (AM type " + temp.template.amType() +
			   "): " + msg);
    }

    public void packetReceived(byte[] packet) {
	if (DEBUG) Dump.dump("Received message", packet);

	if (packet[0] != Serial.TOS_SERIAL_ACTIVE_MESSAGE_ID)
	    return; // not for us.

	SerialPacket msg = new SerialPacket(packet, 1);
	Integer type = new Integer(msg.get_header_type());
	Vector vec = (Vector)templateTbl.get(type);
	if (vec == null) {
	    if (DEBUG) Dump.dump("Received packet with type " + type +
				 ", but no listeners registered", packet);
	    return;
	}
	int length = msg.get_header_length();

	Enumeration en = vec.elements();
	while (en.hasMoreElements()) {
	    msgTemplate temp = (msgTemplate)en.nextElement();

	    Message received;

	    // Erk - end up cloning the message multiple times in case
	    // different templates used for different listeners
	    try {
		received = temp.template.clone(length);
		received.dataSet(msg.dataGet(), msg.offset_data(0) + msg.baseOffset(), 0, length);
	    } catch (ArrayIndexOutOfBoundsException e) {
		error(temp, "invalid length message received (too long)");
		continue;
	    } catch (Exception e) {
		error(temp, "couldn't clone message!");
		continue;
	    }

	    /* Messages that are longer than the template might have
	       a variable-sized array at their end */
	    if (temp.template.dataGet().length > length) {
		error(temp, "invalid length message received (too short)");
		continue;
	    }
	    temp.listener.messageReceived(msg.get_header_addr(), received);
	}
    }
}