Package com.yahoo.messagebus

Class Messenger

java.lang.Object

com.yahoo.messagebus.Messenger

All Implemented Interfaces:

java.lang.Runnable

public class Messenger
extends java.lang.Object
implements java.lang.Runnable

This class implements a single thread that is able to process arbitrary tasks. Tasks are enqueued using the synchronized enqueue(Task) method, and are run in the order they were enqueued.

Author:

Simon Thoresen Hult

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Messenger.Task	Defines the required interface for tasks to be posted to this worker.

Constructor Summary

Constructors

Constructor	Description
Messenger()

Method Summary

Modifier and Type	Method	Description
void	deliverMessage(Message msg, MessageHandler handler)	Convenience method to post a Messenger.Task that delivers a Message to a MessageHandler to the queue of tasks to be executed.
void	deliverReply(Reply reply, ReplyHandler handler)	Convenience method to post a Messenger.Task that delivers a Reply to a ReplyHandler to the queue of tasks to be executed.
boolean	destroy()	Sets the destroyed flag to true.
void	enqueue(Messenger.Task task)	Enqueues the given task in the list of tasks that this worker is to process.
void	run()
void	start()	Starts the internal thread.
void	sync()	Handshakes with the internal thread.

Methods inherited from class java.lang.Object

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

Constructor Detail

Messenger

public Messenger()

Method Detail

start

public void start()

Starts the internal thread. This must be done AFTER all recurrent tasks have been added.

See Also:

addRecurrentTask(Task)

deliverMessage

public void deliverMessage(Message msg,
                           MessageHandler handler)

Convenience method to post a Messenger.Task that delivers a Message to a MessageHandler to the queue of tasks to be executed.

Parameters:

msg - The message to send.

handler - The handler to send to.

deliverReply

public void deliverReply(Reply reply,
                         ReplyHandler handler)

Convenience method to post a Messenger.Task that delivers a Reply to a ReplyHandler to the queue of tasks to be executed.

Parameters:

reply - The reply to return.

handler - The handler to return to.

enqueue

public void enqueue(Messenger.Task task)

Enqueues the given task in the list of tasks that this worker is to process. If this thread has been destroyed previously, this method invokes Messenger.Task.destroy().

Parameters:

task - The task to enqueue.

sync

public void sync()

Handshakes with the internal thread. If this method is called using the messenger thread, this will deadlock.

destroy

public boolean destroy()

Sets the destroyed flag to true. The very first time this method is called, it cleans up all its dependencies. Even if you retain a reference to this object, all of its content is allowed to be garbage collected.

Returns:

True if content existed and was destroyed.

run

public void run()

Specified by:

run in interface java.lang.Runnable