Package eu.bandm.tools.message

Class MessageAsync<M extends Message>

java.lang.Object

eu.bandm.tools.message.SingleSender<M>

eu.bandm.tools.message.MessagePasser<M>

eu.bandm.tools.message.MessageAsync<M>

Type Parameters:

M - the type of the messages

All Implemented Interfaces:

MessageReceiver<M>, AutoCloseable

public class MessageAsync<M extends Message>
extends MessagePasser<M>
implements AutoCloseable

A subclass of SingleSender which lets the drain's receive method run asynchronouously in a separate thread.

All received messages are stored internally in a buffer, and the MessageReceiver.receive(Message) method of the currently set SingleSender.drain is executed in a loop in an own, specially constructed Thread, consuming all these messages asynchronouously.

The caller of the here defined receive(Message) thus returns immediately, after writing the message into a buffer object. (This is currently a LinkedBlockingQueue.)

Once an instance of this class has been closed, sending to it is no longer possible.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) boolean	interrupted	Flag which reflects the state of the thread.
(package private) final LinkedBlockingQueue<M>	queue	Buffer for the written messages, waiting to be delivered asynchronouously to the drain.
(package private) boolean	running	Flag which reflects the state of the thread.
(package private) final Thread	thread	Thread which reads the buffer queue and sends it contents asynchronouously to the drain SingleSender.drain.

Fields inherited from class eu.bandm.tools.message.SingleSender

drain

Constructor Summary

Constructors

Constructor	Description
MessageAsync()	After calling this constructor, a call to SingleSender.setDrain(MessageReceiver) is necessary before SingleSender.send(Message) can be used.
MessageAsync(MessageReceiver<? super M> r)	Constructor which sets the drain.

Method Summary

Modifier and Type	Method	Description
void	close()	Interrupt the consuming thread to process all remaining messages, and forbid further receives by this instance.
void	receive(M m)	Returns immediately after storing the message to the internal buffer.

Methods inherited from class eu.bandm.tools.message.SingleSender

getDrain, getReceiver, send, setDrain, setReceiver

Methods inherited from class java.lang.Object

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

Methods inherited from interface eu.bandm.tools.message.MessageReceiver

ifSubcriticalThen, ifSubcriticalThen, ifSubcriticalThenElse

Field Details

queue

final LinkedBlockingQueue<M extends Message> queue

Buffer for the written messages, waiting to be delivered asynchronouously to the drain.

interrupted

boolean interrupted

Flag which reflects the state of the thread.

running

boolean running

Flag which reflects the state of the thread.

thread

final Thread thread

Thread which reads the buffer queue and sends it contents asynchronouously to the drain SingleSender.drain.

Constructor Details

MessageAsync

public MessageAsync()

After calling this constructor, a call to SingleSender.setDrain(MessageReceiver) is necessary before SingleSender.send(Message) can be used. Otherwise code will crash intentionally. Cf the documentation of the super constructor.

MessageAsync

public MessageAsync(MessageReceiver<? super M> r)

Constructor which sets the drain.

Parameters:

r - the drain.

Method Details

close

public void close()

Interrupt the consuming thread to process all remaining messages, and forbid further receives by this instance.

Specified by:

close in interface AutoCloseable

receive

public void receive(M m)

Returns immediately after storing the message to the internal buffer.

Will block whenever this buffer is full. Normally this should never happen, since the consumer thread should not starve under normal scheduling discipline.

Overrun is probably caused by kamikaze behaviour of the producer(s), since the buffer has a capacity of Integer.MAX_VALUE messages.

Specified by:

receive in interface MessageReceiver<M extends Message>

Overrides:

receive in class MessagePasser<M extends Message>

Parameters:

m - the message to propagate

Throws:

IllegalStateException - when this instance has been closed before.