edu.rice.hj.runtime.actors

Class Actor<MessageType>

java.lang.Object

edu.rice.hj.runtime.actors.Actor<MessageType>

Type Parameters:

MessageType - The type of messages accepted by the actor.

All Implemented Interfaces:

HjActor<MessageType>

public abstract class Actor<MessageType>
extends Object
implements HjActor<MessageType>

The actor uses a concurrent linked-list of DDCs to store and process messages. Synchronous DDCs are used to implement the pause/resume feature.

Concrete subclasses are required to implement the process(Message) method. Typical uses will have sequential code inside process(), but this implementations allows use of any of the HJ parallel primitives inside the process() body.

This actor implementation uses ordered sends:
If actor A1 sends two messages M1 and M2 to Actor A2, A2 will process M1 before M2. No guarantee is however provided for ordering while processing messages from another actor A3 with respect to messages from A1.

Details: Integrating Task Parallelism with Actors. Shams Imam, Vivek Sarkar. Conference on Object-Oriented Programming, Systems, Languages, and Applications (OOPSLA), October 2012.

Author:

Shams Imam (shams@rice.edu), Vivek Sarkar (vsarkar@rice.edu)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Actor.EventType
protected static class	Actor.MessageData<MessageType>

Field Summary

Fields

Modifier and Type	Field and Description
int	actorId

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Actor() No-args constructor.
protected	Actor(boolean pAlwaysSequentialBody) Constructor for Actor.

Method Summary

Modifier and Type	Method and Description
void	exit() Call this to signal intention for the actor to terminate.
protected void	handleThrowable(Throwable th) handleThrowable.
boolean	hasStarted() Returns true if the actor has laready been started;
protected void	onPostExit() Convenience: specify code to be executed after actor is terminated
protected void	onPostStart() Convenience: specify code to be executed after actor is started
protected void	onPreExit() Convenience: specify code to be executed before actor is terminated
protected void	onPreStart() Convenience: specify code to be executed before actor is started
void	pause() Pauses the actor, i.e. the actors stops processing messages in its mailbox.
protected abstract void	process(MessageType theMsg) Callback allowing user to have custom behavior while processing messages.
void	resume() Resumes a paused actor, i.e. the actor resumes processing messages from its mailbox.
void	send(MessageType message) Sends a message to the Actor.
void	start() Causes the actor to start processing messages that have been sent to it. pause() messages before the actor was started are ignored.
void	start(HjPlace hjPlace) Causes the actor to start processing messages that have been sent to it. pause() messages before the actor was started are ignored.
protected void	tryProcessMessage() Try and process message from an active mailbox.

Methods inherited from class java.lang.Object

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

Field Detail

actorId

public final int actorId

Constructor Detail

Actor

protected Actor()

No-args constructor.

Actor

protected Actor(boolean pAlwaysSequentialBody)

Constructor for Actor.

Parameters:

pAlwaysSequentialBody - (Optimization flag) Explicit notification from user for sequential message processing body

Method Detail

hasStarted

public final boolean hasStarted()

Returns true if the actor has laready been started;

Returns:

true if the actor has laready been started

start

public final void start()

Causes the actor to start processing messages that have been sent to it. pause() messages before the actor was started are ignored.

Specified by:

start in interface HjActor<MessageType>

start

public final void start(HjPlace hjPlace)

Causes the actor to start processing messages that have been sent to it. pause() messages before the actor was started are ignored.

Specified by:

start in interface HjActor<MessageType>

exit

public final void exit()

Call this to signal intention for the actor to terminate.

Specified by:

exit in interface HjActor<MessageType>

send

public final void send(MessageType message)

Sends a message to the Actor. This (recipient) actor will asynchronously process this message if it has not exited.

Specified by:

send in interface HjActor<MessageType>

Parameters:

message - The message to send to this actor

Throws:

IllegalArgumentException - if the message is null

pause

public void pause()

Pauses the actor, i.e. the actors stops processing messages in its mailbox.

This method is not thread safe, should only be called in threadsafe manner to avoid data races

Specified by:

pause in interface HjActor<MessageType>

resume

public void resume()
            throws IllegalStateException

Resumes a paused actor, i.e. the actor resumes processing messages from its mailbox.

Specified by:

resume in interface HjActor<MessageType>

Throws:

IllegalStateException - when resume() called when the actor is not in a paused state

onPreStart

protected void onPreStart()

Convenience: specify code to be executed before actor is started

onPostStart

protected void onPostStart()

Convenience: specify code to be executed after actor is started

onPreExit

protected void onPreExit()

Convenience: specify code to be executed before actor is terminated

onPostExit

protected void onPostExit()

Convenience: specify code to be executed after actor is terminated

process

protected abstract void process(MessageType theMsg)

Callback allowing user to have custom behavior while processing messages.

Parameters:

theMsg - message to process

tryProcessMessage

protected void tryProcessMessage()

Try and process message from an active mailbox. Do nothing if no active message is found.

handleThrowable

protected void handleThrowable(Throwable th)

handleThrowable.

Parameters:

th - The exception that occurred while processing a message.