org.codehaus.gpars

groovyx.gpars.actor
[Java] Class DefaultActor

java.lang.Object
  groovyx.gpars.serial.WithSerialId
      groovyx.gpars.actor.impl.MessageStream
          groovyx.gpars.actor.Actor
              groovyx.gpars.actor.AbstractLoopingActor
                  groovyx.gpars.actor.DefaultActor

public class DefaultActor
extends AbstractLoopingActor

The DefaultActor class is the base for all stateful actors, who need to maintain implicit state between subsequent message arrivals. Allowing the actor creator to structure code in a continuation-like style with message retrieval react commands mixed within normal code makes implementation of some algorithms particularly easy.

The DefaultActor upon start-up will grab a thread from the associated actor thread pool and run its body. The body is either the parameter passed to the constructor, or the act() method, if no parameter has been set. The parameter takes precedence over the act() method. Once a react() method call is discovered within the actor's body, its Closure-typed parameter will be scheduled for processing on next message arrival. To preserve the actor principle of at-most-one active thread per actor, the next message, however, will only be handled once the currently run code finishes and frees the current thread. It is thus advisable to avoid code after call to react(). The loop() method will ensure its body is executed repeatedly, until the actor either finishes or an optional loop condition is not met.

Authors:
Vaclav Pech Date: Nov 4th 2010


Field Summary
private static java.lang.String EXPECTED

private groovy.lang.Closure afterLoopCode

private groovy.lang.Closure loopClosure

private java.lang.Runnable loopCode

Misused also for the code to run at start-up

private java.util.concurrent.Callable loopCondition

private groovy.lang.Closure nextContinuation

private static long serialVersionUID

private boolean started

 
Fields inherited from class AbstractLoopingActor
core, currentSender, currentTimerTask, serialVersionUID, stoppedFlag, terminatedFlag, terminatingFlag, timeoutCounter
 
Fields inherited from class Actor
ACTOR_HAS_ALREADY_BEEN_STARTED, AFTER_START, CANNOT_SEND_REPLIES_NO_SENDER_HAS_BEEN_REGISTERED, EMPTY_ARGUMENTS, ON_DELIVERY_ERROR, RESPONDS_TO, START_MESSAGE, STOP_MESSAGE, TERMINATE_MESSAGE, TIMEOUT, TIMEOUT_MESSAGE, currentActorPerThread, currentThread, joinLatch, onStop, parallelGroup, serialVersionUID, timer
 
Fields inherited from class MessageStream
serialVersionUID
 
Fields inherited from class WithSerialId
serialHandle, serialVersionUID
 
Constructor Summary
DefaultActor()

Creates an actor, which will execute its act() methods

DefaultActor(java.lang.Runnable code)

Creates an actor, which will execute the supplied code

 
Method Summary
protected void act()

If no parameter is provided at construction time, the act() method becomes the actor's body

private static void checkForBodyArguments(groovy.lang.Closure closure)

private static void checkForMessageHandlerArguments(groovy.lang.Closure code)

private static void checkForNull(java.lang.Runnable code)

private void doLoop(java.util.concurrent.Callable condition, groovy.lang.Closure afterLoopCode, java.lang.Runnable code)

Ensures that the supplied closure will be invoked repeatedly in a loop.

private groovy.lang.Closure enhanceClosure(groovy.lang.Closure closure)

private boolean evalLoopCondition()

protected void handleStart()

Called once the START_MESSAGE arrives.

void loop(java.lang.Runnable code)

Ensures that the supplied closure will be invoked repeatedly in a loop.

protected void loop(int numberOfLoops, java.lang.Runnable code)

Ensures that the supplied closure will be invoked repeatedly in a loop.

protected void loop(int numberOfLoops, groovy.lang.Closure afterLoopCode, java.lang.Runnable code)

Ensures that the supplied closure will be invoked repeatedly in a loop.

protected void loop(groovy.lang.Closure condition, java.lang.Runnable code)

Ensures that the supplied closure will be invoked repeatedly in a loop.

protected void loop(groovy.lang.Closure condition, groovy.lang.Closure afterLoopCode, java.lang.Runnable code)

Ensures that the supplied closure will be invoked repeatedly in a loop.

void onMessage(java.lang.Object message)

Handles all incoming messages

void react(groovy.lang.Closure code)

Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure.

protected void react(groovy.time.Duration duration, groovy.lang.Closure code)

Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure.

protected void react(long timeout, java.util.concurrent.TimeUnit timeUnit, groovy.lang.Closure code)

Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure.

protected void react(long timeout, groovy.lang.Closure code)

Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure.

private void runAfterLoopCode(groovy.lang.Closure afterLoopCode)

Actor silentStart()

Not supported by DefaultActor

Actor start()

Starts the Actor and sends it the START_MESSAGE to run any afterStart handlers.

 
Methods inherited from class AbstractLoopingActor
cancelCurrentTimeoutTask, doStart, getCore, getSender, hasBeenStopped, initialize, isActive, isFair, makeFair, reply, replyIfExists, runEnhancedWithoutRepliesOnMessages, send, setParallelGroup, setTimeout, silentStart, start, stop, sweepNextMessage, terminate
 
Methods inherited from class Actor
callDynamic, createActorMessage, createRemoteHandle, deregisterCurrentActorWithThread, getJoinLatch, getParallelGroup, handleException, handleInterrupt, handleStart, handleTermination, handleTimeout, hasBeenStopped, isActive, isActorThread, join, join, join, join, onStop, registerCurrentActorWithThread, sendAndContinue, setParallelGroup, silentStart, start, stop, sweepNextMessage, sweepQueue, terminate, threadBoundActor
 
Methods inherited from class MessageStream
call, getRemoteClass, leftShift, reInterrupt, send, send, send, sendAndWait, sendAndWait, sendAndWait
 
Methods inherited from class WithSerialId
createRemoteHandle, getOrCreateSerialHandle, getRemoteClass, writeReplace
 
Methods inherited from class java.lang.Object
java.lang.Object#wait(long), java.lang.Object#wait(), java.lang.Object#wait(long, int), java.lang.Object#equals(java.lang.Object), java.lang.Object#toString(), java.lang.Object#hashCode(), java.lang.Object#getClass(), java.lang.Object#notify(), java.lang.Object#notifyAll()
 

Field Detail

EXPECTED

private static final java.lang.String EXPECTED


afterLoopCode

private groovy.lang.Closure afterLoopCode


loopClosure

private groovy.lang.Closure loopClosure


loopCode

private java.lang.Runnable loopCode
Misused also for the code to run at start-up


loopCondition

private java.util.concurrent.Callable loopCondition


nextContinuation

private groovy.lang.Closure nextContinuation


serialVersionUID

private static final long serialVersionUID


started

private boolean started


 
Constructor Detail

DefaultActor

public DefaultActor()
Creates an actor, which will execute its act() methods


DefaultActor

public DefaultActor(java.lang.Runnable code)
Creates an actor, which will execute the supplied code
Parameters:
code - A Runnable or Closure to be considered the actor's body


 
Method Detail

act

protected void act()
If no parameter is provided at construction time, the act() method becomes the actor's body


checkForBodyArguments

private static void checkForBodyArguments(groovy.lang.Closure closure)


checkForMessageHandlerArguments

private static void checkForMessageHandlerArguments(groovy.lang.Closure code)


checkForNull

private static void checkForNull(java.lang.Runnable code)


doLoop

@SuppressWarnings({"OverlyComplexBooleanExpression"})
private void doLoop(java.util.concurrent.Callable condition, groovy.lang.Closure afterLoopCode, java.lang.Runnable code)
Ensures that the supplied closure will be invoked repeatedly in a loop. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
condition - A condition to evaluate before each iteration starts. If the condition returns false, the loop exits.
afterLoopCode - Code to run after the main actor's loop finishes
code - The closure to invoke repeatedly


enhanceClosure

private groovy.lang.Closure enhanceClosure(groovy.lang.Closure closure)


evalLoopCondition

private boolean evalLoopCondition()


handleStart

@Override
protected void handleStart()
Called once the START_MESSAGE arrives. We need to run the actor's body here, letting it set nextContinuation to hols the next message handler


loop

public final void loop(java.lang.Runnable code)
Ensures that the supplied closure will be invoked repeatedly in a loop. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
code - The closure to invoke repeatedly


loop

protected final void loop(int numberOfLoops, java.lang.Runnable code)
Ensures that the supplied closure will be invoked repeatedly in a loop. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
numberOfLoops - The loop will only be run the given number of times
code - The closure to invoke repeatedly


loop

protected final void loop(int numberOfLoops, groovy.lang.Closure afterLoopCode, java.lang.Runnable code)
Ensures that the supplied closure will be invoked repeatedly in a loop. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
numberOfLoops - The loop will only be run the given number of times
afterLoopCode - Code to run after the main actor's loop finishes
code - The closure to invoke repeatedly


loop

protected final void loop(groovy.lang.Closure condition, java.lang.Runnable code)
Ensures that the supplied closure will be invoked repeatedly in a loop. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
condition - A condition to evaluate before each iteration starts. If the condition returns false, the loop exits.
code - The closure to invoke repeatedly


loop

protected final void loop(groovy.lang.Closure condition, groovy.lang.Closure afterLoopCode, java.lang.Runnable code)
Ensures that the supplied closure will be invoked repeatedly in a loop. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
condition - A condition to evaluate before each iteration starts. If the condition returns false, the loop exits.
afterLoopCode - Code to run after the main actor's loop finishes
code - The closure to invoke repeatedly


onMessage

final void onMessage(java.lang.Object message)
Handles all incoming messages
Parameters:
message - The current message to process


react

public final void react(groovy.lang.Closure code)
Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
code - The code to handle the next message. The reply() and replyIfExists() methods are available inside the closure to send a reply back to the actor, which sent the original message.


react

protected final void react(groovy.time.Duration duration, groovy.lang.Closure code)
Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
duration - Time to wait at most for a message to arrive. The actor terminates if a message doesn't arrive within the given timeout. The TimeCategory DSL to specify timeouts must be enabled explicitly inside the Actor's act() method.
code - The code to handle the next message. The reply() and replyIfExists() methods are available inside the closure to send a reply back to the actor, which sent the original message.


react

protected final void react(long timeout, java.util.concurrent.TimeUnit timeUnit, groovy.lang.Closure code)
Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure. The method never returns, but instead frees the processing thread back to the thread pool.
Parameters:
timeout - Time in milliseconds to wait at most for a message to arrive. The actor terminates if a message doesn't arrive within the given timeout.
timeUnit - a TimeUnit determining how to interpret the timeout parameter
code - The code to handle the next message. The reply() and replyIfExists() methods are available inside the closure to send a reply back to the actor, which sent the original message.


react

protected final void react(long timeout, groovy.lang.Closure code)
Schedules an ActorAction to take the next message off the message queue and to pass it on to the supplied closure. The method never returns, but instead frees the processing thread back to the thread pool. Also adds reply() and replyIfExists() methods to the currentActor and the message. These methods will call send() on the target actor (the sender of the original message). The reply()/replyIfExists() methods invoked on the actor will be sent to all currently processed messages, reply()/replyIfExists() invoked on a message will send a reply to the sender of that particular message only.
Parameters:
timeout - Time in milliseconds to wait at most for a message to arrive. The actor terminates if a message doesn't arrive within the given timeout.
code - The code to handle the next message. The reply() and replyIfExists() methods are available inside the closure to send a reply back to the actor, which sent the original message.


runAfterLoopCode

private void runAfterLoopCode(groovy.lang.Closure afterLoopCode)


silentStart

@Override
public Actor silentStart()
Not supported by DefaultActor
Returns:
same actor


start

@Override
public Actor start()
Starts the Actor and sends it the START_MESSAGE to run any afterStart handlers. No messages can be sent or received before an Actor is started.
Returns:
same actor


 

Copyright © 2008–2010 Václav Pech. All Rights Reserved.