net.jini.discovery

Class AbstractLookupDiscovery.Requestor

java.lang.Object

java.lang.Thread

net.jini.discovery.AbstractLookupDiscovery.Requestor

All Implemented Interfaces:

Runnable

Enclosing class:

AbstractLookupDiscovery

private class AbstractLookupDiscovery.Requestor
extends Thread

Thread that periodically sends out multicast requests for a limited period of time, and then exits.

An instance of this thread is run at startup, and each time the set of groups to discover is changed.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	delayFlag
private String[]	groups Groups to request
private int	responsePort Unicast response port
private MulticastSocket	sock Multicast socket for sending packets

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor and Description
Requestor(String[] groups, int port, boolean delayFlag)

Method Summary

Modifier and Type	Method and Description
void	run() This method sends out N (for small N) multicast requests.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

sock

private final MulticastSocket sock

Multicast socket for sending packets

responsePort

private final int responsePort

Unicast response port

groups

private final String[] groups

Groups to request

delayFlag

private final boolean delayFlag

Constructor Detail

Requestor

public Requestor(String[] groups,
                 int port,
                 boolean delayFlag)
          throws IOException

Throws:

IOException

Method Detail

run

public void run()

This method sends out N (for small N) multicast requests. Until the last request is sent out, this method sleeps for 5 seconds after each request is sent. After the last request is sent, this method sleeps for 2 minutes to allow the ResponseListener time to receive and process any multicast responses sent in reply to the multicast requests. Before sending a request, a new multicast request is constructed so that updates can be made to the set of service IDs of the lookup services discovered due to previous requests.

After all requests have been sent, and the ResponseListener has been given the appropriate time to receive and process any multicast responses, if there are no more active instances of this thread, this method terminates (interrupts) the ResponseListener. Note that although it is more desirable to have the ResponseListener set a timeout on the server socket (using setSoTimeout) and then simply exit after a period of time in which both the ResponseListener has been idle, and there have been no active Requestor threads, using setSoTimeout in this way can cause random hangs on the Solaris(TM) operating system.

Specified by:

run in interface Runnable

Overrides:

run in class Thread