Gpars_supervisor.groovy

import groovyx.gpars.actor.Actors
import groovyx.gpars.actor.DefaultActor
import groovyx.gpars.actor.DynamicDispatchActor

class SupervisedException extends Exception {
    SupervisedException(String message) {
        super(message)
    }
}

class Supervised extends DefaultActor {
    Supervisor supervisor
    
    void onException(Throwable th) {
        supervisor << new SupervisedException(th.message)
    }
}

class Supervisor extends DynamicDispatchActor {
    Supervised supervised

    void link(Supervised supervised) {
        this.supervised = supervised
        this.supervised.supervisor = this
    }
}

def supervised = new Supervised() {
    void act() {
        loop {
            react { String message ->
                if (message == 'gift') {
                    throw new Exception(message)
                }
                println "NORMAL: $message"
            }
        }
    }
}.start()

def supervisor = new Supervisor() {
    void onMessage(String query) {
        supervised << query
    }
    void onMessage(SupervisedException ex) {
        println "SUPERVISED ACTOR DIES WITH MESSAGE: ${ex.message}"
        supervised = Actors.actor { react { println it } }
    }
}.start()

supervisor.link(supervised)

supervisor << "something"
Thread.sleep(1000)
supervisor << "something"
Thread.sleep(1000)
supervisor << "gift"
Thread.sleep(2000)
supervisor << "Message processed by a new supervised instance"