On Thu, Jun 12, 2014 at 9:50 PM, Swathi Sri Kondagari <
[email protected]> wrote:
> Hi
>
> Thanks a lot for the reply. I got to start working on a custom made
> solution according to the line of thought you had provided. But according
> to the suggestion *I couldn't get a hold of the actorref that was failing
> in the decider function of the onetoonestrategy to include book keeping*.
>
You can use getSender() from the decider to get hold of the ActorRef of the
failing child actor.
/Patrik
> I have included one way of book keeping by defining a *new strategy which
> extends a normal supervisor strategy* class. *The default strategy for
> this custom strategy class* is defined by a oneforonestrategy with 40
> retrials and a decider which when sent in a null pointer exception just
> tries to restart. *The handle failure of the custom strategy class is
> also overriden* in order to keep count of the numver of times the current
> child actor has failed. If the number exceeds 5 , a error sent to an error
> queue and the poststop method of the child actor class is called so that it
> kills the child class.
> Please suggest if I am missing something or if this is a work around and
> if there is a simpler way to acheive the same.
>
> Thanks,
> Swathi
>
> *Custom Supervisor Strategy* class defined to extend a normal
> supervisorstrategy with overriden default strategy and handlefailure
> methods to stop resending a message after five trials.
>
>
> class CustomSupervisorStrategy extends SupervisorStrategy{
>
> public static final SupervisorStrategy defaultStrategy() {
> return new OneForOneStrategy(40,Duration.create("1 minute"),new
> Function<Throwable, Directive>() {
> Directive apply(Throwable t) {
> if (t instanceof ArithmeticException) {
> return resume();
> } else if (t instanceof NullPointerException) {
> println "this is null pointer exception 1"
> return restart()
> } else if (t instanceof IllegalArgumentException) {
> return stop();
> } else if(t instanceof ActorKilledException){
> println t
> return restart()
> } else {
> return escalate()
> }
> }
> });
> }
>
> @Override
> PartialFunction<Throwable, Directive> decider() {
> return defaultDecider()
> }
>
> @Override
> void handleChildTerminated(ActorContext actorContext, ActorRef
> actorRef, scala.collection.Iterable<ActorRef> actorRefIterable) {
> println "comes to child terminated"
> defaultStrategy().handleChildTerminated(actorContext, actorRef,
> actorRefIterable)
> }
>
> @Override
> void processFailure(ActorContext actorContext, boolean b, ActorRef
> actorRef, Throwable throwable, ChildRestartStats childRestartStats,
> scala.collection.Iterable<ChildRestartStats> childRestartStatsIterable) {
>
> defaultStrategy().processFailure(actorContext,b,actorRef,throwable,childRestartStats,childRestartStatsIterable)
> }
>
> @Override
> public boolean handleFailure(ActorContext context,
> ActorRef child,
> java.lang.Throwable cause,
> ChildRestartStats stats,
>
> scala.collection.Iterable<ChildRestartStats> children){
> println "reached the handle failure"
> println stats
> println children
> if(stats.maxNrOfRetriesCount() < 5) {
>
> defaultStrategy().handleFailure(context,child,cause,stats,children)
> } else {
> // TODO : define a service which can post this message to a jms error
> queue.
> child.postStop()
> }
> }
> }
>
>
>
> *RetrySupervisor class* - a supervisor class which is used to
> instantiate the child class and define the strategy that will used to
> handle the exceptions that occur in the child class
>
>
> class RetrySupervisor extends UntypedActor{
>
> private static CustomSupervisorStrategy strategy = new
> CustomSupervisorStrategy()
>
> @Override
> public CustomSupervisorStrategy supervisorStrategy() {
> return strategy;
> }
> public void onReceive(Object o) {
> if (o instanceof Props) {
> getSender().tell(getContext().actorOf((Props) o), getSelf());
> } else if(o instanceof Terminated){
> println "supervisor got this Terminated" + o
> unhandled(o);
> } else {
> println "Supervisor got a random message"
> }
> }
> }
>
>
>
> *Retry Child class:* It is anormal class which throws an error if the
> sent message is 42.
>
>
> class RetryChild extends UntypedActor{
>
> int state = 1;
> public void onReceive(Object o) throws Exception {
>
> if (o instanceof Exception) {
> throw (Exception) o;
> } else if (o instanceof Terminated) {
> println "terminated"
> } else if (o instanceof Integer) {
> println "the current message " + o
> if(o == 42) {
> throw new NullPointerException()
> }
> } else if (o.equals("get")) {
> println "in get function " + o
> getSender().tell(state , getSelf());
>
> } else {
> println "In unhandled " + o
> unhandled(o);
> }
> }
>
> @Override
> public void preRestart(Throwable reason, Option<Object> message ) {
> getContext().self().tell(message.get(),ActorRef.noSender())
> }
>
> @Override
> public void postStop() {
> println "post stop simple"
> }
>
> }
>
> *The funciton call to send a message for a failure scenario*:
>
> Duration timeout = Duration.create(50,TimeUnit.SECONDS)
> def system = ActorSystem.create("system")
> Props superProps = Props.create(RetrySupervisor.class)
> ActorRef retrySupervisor = system.actorOf(superProps,
> "retrySupervisor")
> ActorRef retryChild = (ActorRef) Await.result(ask(retrySupervisor,
> Props.create(RetryChild.class), 50000),timeout);
> retryChild.tell(42 , ActorRef.noSender())
>
> --
> >>>>>>>>>> Read the docs: http://akka.io/docs/
> >>>>>>>>>> Check the FAQ:
> http://doc.akka.io/docs/akka/current/additional/faq.html
> >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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--
Patrik Nordwall
Typesafe <http://typesafe.com/> - Reactive apps on the JVM
Twitter: @patriknw
<http://www.scaladays.org/>
--
>>>>>>>>>> Read the docs: http://akka.io/docs/
>>>>>>>>>> Check the FAQ:
>>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html
>>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user
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