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=doc #18128 explain PoisonPill interaction with PA

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Konrad Malawski 2015-08-19 18:20:13 +02:00
parent 7679b7e63f
commit 8c4cc9a93f
14 changed files with 341 additions and 22 deletions
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73
akka-docs/rst/java/code/docs/persistence/PersistenceDocTest.java
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@ -13,7 +13,6 @@ import akka.japi.Function;
import akka.japi.Procedure;
import akka.persistence.*;
import scala.Option;
import java.io.Serializable;
public class PersistenceDocTest {
@ -504,7 +503,7 @@ public class PersistenceDocTest {
}
};
static Object o13 = new Object() {
static Object o14 = new Object() {
//#view
class MyView extends UntypedPersistentView {
@Override
@ -534,4 +533,74 @@ public class PersistenceDocTest {
//#view-update
}
};
static Object o13 = new Object() {
//#safe-shutdown
final class Shutdown {}
class MyPersistentActor extends UntypedPersistentActor {
@Override
public String persistenceId() {
return "some-persistence-id";
}
@Override
public void onReceiveCommand(Object msg) throws Exception {
if (msg instanceof Shutdown) {
context().stop(self());
} else if (msg instanceof String) {
System.out.println(msg);
persist("handle-" + msg, new Procedure<String>() {
@Override
public void apply(String param) throws Exception {
System.out.println(param);
}
});
} else unhandled(msg);
}
@Override
public void onReceiveRecover(Object msg) throws Exception {
// handle recovery...
}
}
//#safe-shutdown
public void usage() {
final ActorSystem system = ActorSystem.create("example");
final ActorRef persistentActor = system.actorOf(Props.create(MyPersistentActor.class));
//#safe-shutdown-example-bad
// UN-SAFE, due to PersistentActor's command stashing:
persistentActor.tell("a", ActorRef.noSender());
persistentActor.tell("b", ActorRef.noSender());
persistentActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
// order of received messages:
// a
// # b arrives at mailbox, stashing; internal-stash = [b]
// # PoisonPill arrives at mailbox, stashing; internal-stash = [b, Shutdown]
// PoisonPill is an AutoReceivedMessage, is handled automatically
// !! stop !!
// Actor is stopped without handling `b` nor the `a` handler!
//#safe-shutdown-example-bad
//#safe-shutdown-example-good
// SAFE:
persistentActor.tell("a", ActorRef.noSender());
persistentActor.tell("b", ActorRef.noSender());
persistentActor.tell(new Shutdown(), ActorRef.noSender());
// order of received messages:
// a
// # b arrives at mailbox, stashing; internal-stash = [b]
// # Shutdown arrives at mailbox, stashing; internal-stash = [b, Shutdown]
// handle-a
// # unstashing; internal-stash = [Shutdown]
// b
// handle-b
// # unstashing; internal-stash = []
// Shutdown
// -- stop --
//#safe-shutdown-example-good
}
};
}