groupmgmt.impl
Class BeaconSender

java.lang.Object
  groupmgmt.impl.BeaconSender

All Implemented Interfaces:

java.lang.Runnable

class BeaconSender

extends java.lang.Object

implements java.lang.Runnable

The BeaconSender class; Responsible for periodically multicasting MemberBeacons. Controlled by the BeaconServer.

Based on the beacon package by Ali Hazemi.

Version:

July 2003

Author:

Christine Julien, Tom Elgin

See Also:

BeaconServer

Field Summary

private MemberBeacon	beacon The MemberBeacon to broadcast.
private java.net.DatagramSocket	dgramSocket The DatagramSocket to send beacons with.
private java.net.InetAddress	mcastAddress The multicast address to send beacons to.
private int	mcastPort The multicast port to send beacons to.
private int	period The period to wait between broadcasts (ms).
private java.lang.Thread	senderThread Thread to do the sending.

Constructor Summary

BeaconSender(java.net.InetAddress mcastAddress, int mcastPort)
Construct a BeaconSender.

Method Summary

MemberBeacon	getBeacon() Accessor to the beacon.
private void	log(java.lang.String msg) For testing.
void	run() Run the BeaconSender thread.
void	sendBeacon() The method that sends the beacon.
void	setBeacon(MemberBeacon beacon) Set the beacon to be broadcasted.
void	setPeriod(int period) Set the period at which the beacon is broadcasted.
void	start() Start sending beacons.
void	stop() Stop sending beacons.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

mcastAddress

private java.net.InetAddress mcastAddress

The multicast address to send beacons to.

mcastPort

private int mcastPort

The multicast port to send beacons to.

dgramSocket

private java.net.DatagramSocket dgramSocket

The DatagramSocket to send beacons with.

senderThread

private volatile java.lang.Thread senderThread

Thread to do the sending.

beacon

private MemberBeacon beacon

The MemberBeacon to broadcast.

period

private int period

The period to wait between broadcasts (ms). Defaults to 1000.

Constructor Detail

BeaconSender

public BeaconSender(java.net.InetAddress mcastAddress,
                    int mcastPort)

Construct a BeaconSender.

Parameters:

mcastAddress - The multicast address to beacon to.

mcastPort - The port to beacon to.

Method Detail

start

public void start()

Start sending beacons.

stop

public void stop()

Stop sending beacons.

setPeriod

public void setPeriod(int period)

Set the period at which the beacon is broadcasted.

Parameters:

period - How often to send the beacon (ms).

setBeacon

public void setBeacon(MemberBeacon beacon)

Set the beacon to be broadcasted.

Parameters:

beacon - The MemberBeacon to broadcast.

getBeacon

public MemberBeacon getBeacon()

Accessor to the beacon.

Returns:

The MemberBeacon currently being broadcasted.

run

public void run()

Run the BeaconSender thread. Sends a datagram message every [period] millisecond to a multicast [address]:[port]. The datagram contains the MemberBeacon object.

Specified by:

run in interface java.lang.Runnable

sendBeacon

public void sendBeacon()

The method that sends the beacon.

log

private void log(java.lang.String msg)

For testing. Output a message to the command line.