GPARS Dynamic Dispatch

GPARS Dynamic Dispatch

import groovyx.gpars.actor.DynamicDispatchActor
import org.codehaus.groovy.runtime.NullObject
import groovy.time.TimeCategory

def actor = new DynamicDispatchActor(){
	private int counter = 0
	void onMessage(String message) {
		counter += message.size()
		println "Actor received string $message"
	}

	void onMessage(Integer message) {
		counter += message
		println "Actor received integer $message"
	}

	void onMessage(Object message) {
		counter += 1
		println 'Actor received object'
	}

	void onMessage(NullObject message) {
		'Actor received a null object. Sending back the current counter value.'
		reply counter
	}
}
actor.start()

actor.send(1)
actor.send("one")

// or the left-shift operator << can be used
actor << 2
actor << "two"

// supposedly the implicit call() method can be used, but it
// failed for me :-(
//actor 3
//actor "three"

// show that this IS async
println "There is no guarantee that this will print AFTER the actor prints its stuff!"

// in onMessage(NullObject) the Actor sends explicit reply, so we get a message back
assert actor.sendAndWait(null) == 9

use(TimeCategory){
	println "Actor will print a response immediately, but this thread will wait"
	println "for a reply.  Because there is no reply in the actor, it will time out."
	assert actor.sendAndWait("NOPE", 5.seconds) == null
}