Class UntypedProcessor

  extended by akka.actor.UntypedActor
      extended by akka.persistence.UntypedProcessor
All Implemented Interfaces:
Actor, Stash, StashFactory, StashSupport, UnrestrictedStash, RequiresMessageQueue<DequeBasedMessageQueueSemantics>, Processor, ProcessorImpl, Recovery, Snapshotter

public abstract class UntypedProcessor
extends UntypedActor
implements Processor

Java API: an actor that persists (journals) messages of type Persistent. Messages of other types are not persisted.

 import akka.persistence.Persistent;
 import akka.persistence.Processor;

 class MyProcessor extends UntypedProcessor {
     public void onReceive(Object message) throws Exception {
         if (message instanceof Persistent) {
             // message has been written to journal
             Persistent persistent = (Persistent)message;
             Object payload = persistent.payload();
             Long sequenceNr = persistent.sequenceNr();
             // ...
         } else {
             // message has not been written to journal

 // ...

 ActorRef processor = getContext().actorOf(Props.create(MyProcessor.class), "myProcessor");

 processor.tell(Persistent.create("foo"), null);
 processor.tell("bar", null);

During start and restart, persistent messages are replayed to a processor so that it can recover internal state from these messages. New messages sent to a processor during recovery do not interfere with replayed messages, hence applications don't need to wait for a processor to complete its recovery.

Automated recovery can be turned off or customized by overriding the preStart and preRestart life cycle hooks. If automated recovery is turned off, an application can explicitly recover a processor by sending it a Recover message.

Persistent messages are assigned sequence numbers that are generated on a per-processor basis. A sequence starts at 1L and doesn't contain gaps unless a processor (logically) deletes a message.

During recovery, a processor internally buffers new messages until recovery completes, so that new messages do not interfere with replayed messages. This internal buffer (the ''processor stash'') is isolated from the ''user stash'' inherited by akka.actor.Stash. Processor implementation classes can therefore use the ''user stash'' for stashing/unstashing both persistent and transient messages.

Processors can also store snapshots of internal state by calling saveSnapshot. During recovery, a saved snapshot is offered to the processor with a SnapshotOffer message, followed by replayed messages, if any, that are younger than the snapshot. Default is to offer the latest saved snapshot.

See Also:
Processor, Recover, PersistentBatch

Nested Class Summary
Nested classes/interfaces inherited from interface akka.persistence.Recovery
Nested classes/interfaces inherited from interface akka.actor.Actor
Constructor Summary
Method Summary
Methods inherited from class akka.actor.UntypedActor
getContext, getSelf, getSender, onReceive, postRestart, postStop, preRestart, preStart, receive, supervisorStrategy, unhandled
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface akka.persistence.Processor
Methods inherited from interface akka.persistence.ProcessorImpl
_persistenceId, aroundPostStop, aroundPreRestart, aroundPreStart, deleteMessage, deleteMessage, deleteMessages, deleteMessages, flushJournalBatch, initializing, instanceId, nextSequenceNr, onRecoveryCompleted, onRecoveryFailure, onReplayFailure, onReplaySuccess, preRestart, preRestartDefault, preStart, processing, processorBatch, processorId, recoveryFinished, recoveryRunning, sequenceNr, snapshotterId, unhandled, unstashFilterPredicate
Methods inherited from interface akka.persistence.Recovery
_currentPersistent, _currentState, _lastSequenceNr, _recoveryFailureCause, _recoveryFailureMessage, aroundReceive, currentPersistentMessage, extension, getCurrentPersistentMessage, journal, lastSequenceNr, prepareRestart, receiverStash, recoveryPending, recoveryStarted, replayFailed, replayStarted, runReceive, snapshotSequenceNr, updateLastSequenceNr, updateLastSequenceNr, withCurrentPersistent
Methods inherited from interface akka.persistence.Snapshotter
deleteSnapshot, deleteSnapshots, loadSnapshot, saveSnapshot, snapshotStore
Methods inherited from interface akka.actor.UnrestrictedStash
Methods inherited from interface akka.actor.Actor
aroundPostRestart, context, postRestart, receive, self, sender, supervisorStrategy
Methods inherited from interface akka.actor.StashSupport
actorCell, capacity, clearStash, context, enqueueFirst, mailbox, prepend, self, stash, theStash, unstash, unstashAll, unstashAll
Methods inherited from interface akka.actor.StashFactory

Constructor Detail


public UntypedProcessor()