package sample.persistence;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.Props;
import akka.japi.Procedure;
import akka.persistence.SnapshotOffer;
import akka.persistence.UntypedPersistentActor;
import akka.persistence.UntypedPersistentView;
import scala.concurrent.duration.Duration;
import java.util.concurrent.TimeUnit;
public class PersistentViewExample {
public static class ExamplePersistentActor extends UntypedPersistentActor {
@Override
public String persistenceId() { return "sample-id-4"; }
private int count = 1;
@Override
public void onReceiveRecover(Object message) {
if (message instanceof String) {
count += 1;
} else {
unhandled(message);
}
}
@Override
public void onReceiveCommand(Object message) {
if (message instanceof String) {
String s = (String) message;
System.out.println(String.format("persistentActor received %s (nr = %d)", s, count));
persist(s + count, new Procedure<String>() {
public void apply(String evt) {
count += 1;
}
});
} else {
unhandled(message);
}
}
}
public static class ExampleView extends UntypedPersistentView {
private int numReplicated = 0;
@Override public String persistenceId() { return "sample-id-4"; }
@Override public String viewId() { return "sample-view-id-4"; }
@Override
public void onReceive(Object message) throws Exception {
if (isPersistent()) {
numReplicated += 1;
System.out.println(String.format("view received %s (num replicated = %d)", message, numReplicated));
} else if (message instanceof SnapshotOffer) {
SnapshotOffer so = (SnapshotOffer)message;
numReplicated = (Integer)so.snapshot();
System.out.println(String.format("view received snapshot offer %s (metadata = %s)", numReplicated, so.metadata()));
} else if (message.equals("snap")) {
saveSnapshot(numReplicated);
} else {
unhandled(message);
}
}
}
public static void main(String... args) throws Exception {
final ActorSystem system = ActorSystem.create("example");
final ActorRef persistentActor = system.actorOf(Props.create(ExamplePersistentActor.class));
final ActorRef view = system.actorOf(Props.create(ExampleView.class));
system.scheduler().schedule(Duration.Zero(), Duration.create(2, TimeUnit.SECONDS), persistentActor, "scheduled", system.dispatcher(), null);
system.scheduler().schedule(Duration.Zero(), Duration.create(5, TimeUnit.SECONDS), view, "snap", system.dispatcher(), null);
}
}