!per #15436 make persistenceId abstract in NEW classes

(cherry picked from commit de3249f7f4b859c3caa232e579d9a3bae7406803)

Conflicts:
	akka-samples/akka-sample-persistence-scala/src/main/scala/sample/persistence/PersistentActorExample.scala

akka-contrib/docs/cluster-sharding.rst

@@ -30,9 +30,11 @@ This is how an entry actor may look like:
 .. includecode:: @contribSrc@/src/test/java/akka/contrib/pattern/ClusterShardingTest.java#counter-actor
 
 The above actor uses event sourcing and the support provided in ``UntypedPersistentActor`` to store its state.
-It does not have to be a processor, but in case of failure or migration of entries between nodes it must be able to recover
+It does not have to be a persistent actor, but in case of failure or migration of entries between nodes it must be able to recover
 its state if it is valuable.
 
+Note how the ``persistenceId`` is defined. You may define it another way, but it must be unique.
+
 When using the sharding extension you are first, typically at system startup on each node
 in the cluster, supposed to register the supported entry types with the ``ClusterSharding.start``
 method. ``ClusterSharding.start`` gives you the reference which you can pass along.
@@ -74,9 +76,11 @@ This is how an entry actor may look like:
 .. includecode:: @contribSrc@/src/multi-jvm/scala/akka/contrib/pattern/ClusterShardingSpec.scala#counter-actor
 
 The above actor uses event sourcing and the support provided in ``PersistentActor`` to store its state.
-It does not have to be a processor, but in case of failure or migration of entries between nodes it must be able to recover
+It does not have to be a persistent actor, but in case of failure or migration of entries between nodes it must be able to recover
 its state if it is valuable.
 
+Note how the ``persistenceId`` is defined. You may define it another way, but it must be unique.
+
 When using the sharding extension you are first, typically at system startup on each node
 in the cluster, supposed to register the supported entry types with the ``ClusterSharding.start``
 method. ``ClusterSharding.start`` gives you the reference which you can pass along.

akka-contrib/src/multi-jvm/scala/akka/contrib/pattern/ClusterShardingSpec.scala

@@ -77,6 +77,10 @@ object ClusterShardingSpec extends MultiNodeConfig {
 
     context.setReceiveTimeout(120.seconds)
 
+    // self.path.parent.name is the type name (utf-8 URL-encoded) 
+    // self.path.name is the entry identifier (utf-8 URL-encoded)
+    override def persistenceId: String = self.path.parent.name + "-" + self.path.name
+
     var count = 0
     //#counter-actor
 

akka-contrib/src/test/java/akka/contrib/pattern/ClusterShardingTest.java

@@ -111,6 +111,13 @@ public class ClusterShardingTest {
     }
 
     int count = 0;
+    
+    // getSelf().path().parent().name() is the type name (utf-8 URL-encoded) 
+    // getSelf().path().name() is the entry identifier (utf-8 URL-encoded)
+    @Override
+    public String persistenceId() {
+      return getSelf().path().parent().name() + "-" + getSelf().path().name();
+    }
 
     @Override
     public void preStart() throws Exception {

akka-docs/rst/java/code/docs/persistence/PersistenceDocTest.java

@@ -133,6 +133,9 @@ public class PersistenceDocTest {
         }
         
         class MyProcessor5 extends UntypedPersistentActor {
+            @Override
+            public String persistenceId() { return "persistence-id"; }
+
             //#recovery-completed
           
             @Override
@@ -356,6 +359,9 @@ public class PersistenceDocTest {
     static Object o8 = new Object() {
         //#reliable-event-delivery
         class MyPersistentActor extends UntypedPersistentActor {
+            @Override
+            public String persistenceId() { return "some-persistence-id"; }
+
             private ActorRef destination;
             private ActorRef channel;
 
@@ -394,6 +400,8 @@ public class PersistenceDocTest {
     static Object o9 = new Object() {
         //#persist-async
         class MyPersistentActor extends UntypedPersistentActor {
+            @Override
+            public String persistenceId() { return "some-persistence-id"; }
 
             @Override
             public void onReceiveRecover(Object msg) {
@@ -441,6 +449,8 @@ public class PersistenceDocTest {
     static Object o10 = new Object() {
         //#defer
         class MyPersistentActor extends UntypedPersistentActor {
+            @Override
+            public String persistenceId() { return "some-persistence-id"; }
 
             @Override
             public void onReceiveRecover(Object msg) {
@@ -486,8 +496,11 @@ public class PersistenceDocTest {
     static Object o11 = new Object() {
         //#view
         class MyView extends UntypedPersistentView {
-          @Override public String viewId() { return "some-persistence-id-view"; }
-          @Override public String persistenceId() { return "some-persistence-id"; }
+            @Override
+            public String persistenceId() { return "some-persistence-id"; }
+            
+            @Override
+            public String viewId() { return "my-stable-persistence-view-id"; }
 
             @Override
             public void onReceive(Object message) throws Exception {
@@ -499,7 +512,6 @@ public class PersistenceDocTest {
                   unhandled(message);
                 }
             }
-
         }
         //#view
 

akka-docs/rst/java/lambda-persistence.rst

@@ -105,7 +105,7 @@ is defined by implementing ``receiveRecover`` and ``receiveCommand``. This is de
 .. includecode:: ../../../akka-samples/akka-sample-persistence-java-lambda/src/main/java/sample/persistence/PersistentActorExample.java#persistent-actor-example
 
 The example defines two data types, ``Cmd`` and ``Evt`` to represent commands and events, respectively. The
-``state`` of the ``ExampleProcessor`` is a list of persisted event data contained in ``ExampleState``.
+``state`` of the ``ExamplePersistentActor`` is a list of persisted event data contained in ``ExampleState``.
 
 The persistent actor's ``receiveRecover`` method defines how ``state`` is updated during recovery by handling ``Evt``
 and ``SnapshotOffer`` messages. The persistent actor's ``receiveCommand`` method is a command handler. In this example,
@@ -139,20 +139,11 @@ It contains instructions on how to run the ``PersistentActorExample``.
 Identifiers
 -----------
 
-A persistent actor must have an identifier that doesn't change across different actor incarnations. It defaults to the
-``String`` representation of persistent actor's path without the address part and can be obtained via the ``persistenceId``
-method.
-
-.. includecode:: ../../../akka-samples/akka-sample-persistence-java-lambda/src/main/java/doc/LambdaPersistenceDocTest.java#persistence-id
-
-Applications can customize a persistent actor's id by specifying an actor name during persistent actor creation as shown in
-section :ref:`event-sourcing-java-lambda`. This changes that persistent actor's name in its actor hierarchy and hence influences only
-part of the persistent actor id. To fully customize a persistent actor's id, the ``persistenceId`` method must be overridden.
+A persistent actor must have an identifier that doesn't change across different actor incarnations.
+The identifier must be defined with the ``persistenceId`` method.
 
 .. includecode:: ../../../akka-samples/akka-sample-persistence-java-lambda/src/main/java/doc/LambdaPersistenceDocTest.java#persistence-id-override
 
-Overriding ``persistenceId`` is the recommended way to generate stable identifiers.
-
 .. _recovery-java-lambda:
 
 Recovery
@@ -329,13 +320,8 @@ Further possibilities to customize initial recovery are explained in section :re
 Identifiers
 -----------
 
-A persistent view must have an identifier that doesn't change across different actor incarnations. It defaults to the
-``String`` representation of the actor path without the address part and can be obtained via the ``viewId``
-method.
-
-Applications can customize a view's id by specifying an actor name during view creation. This changes that persistent view's
-name in its actor hierarchy and hence influences only part of the view id. To fully customize a view's id, the
-``viewId`` method must be overridden. Overriding ``viewId`` is the recommended way to generate stable identifiers.
+A persistent view must have an identifier that doesn't change across different actor incarnations.
+The identifier must be defined with the ``viewId`` method.
 
 The ``viewId`` must differ from the referenced ``persistenceId``, unless :ref:`snapshots-java-lambda` of a view and its
 persistent actor shall be shared (which is what applications usually do not want).

akka-docs/rst/java/persistence.rst

@@ -107,7 +107,7 @@ is defined by implementing ``receiveRecover`` and ``receiveCommand``. This is de
 .. includecode:: ../../../akka-samples/akka-sample-persistence-java/src/main/java/sample/persistence/PersistentActorExample.java#persistent-actor-example
 
 The example defines two data types, ``Cmd`` and ``Evt`` to represent commands and events, respectively. The
-``state`` of the ``ExampleProcessor`` is a list of persisted event data contained in ``ExampleState``.
+``state`` of the ``ExamplePersistentActor`` is a list of persisted event data contained in ``ExampleState``.
 
 The persistent actor's ``onReceiveRecover`` method defines how ``state`` is updated during recovery by handling ``Evt``
 and ``SnapshotOffer`` messages. The persistent actor's ``onReceiveCommand`` method is a command handler. In this example,
@@ -141,19 +141,11 @@ It contains instructions on how to run the ``PersistentActorExample``.
 Identifiers
 -----------
 
-A persistent actor must have an identifier that doesn't change across different actor incarnations. It defaults to the
-``String`` representation of persistent actor's path without the address part and can be obtained via the ``persistenceId``
-method.
-
-.. includecode:: code/docs/persistence/PersistenceDocTest.java#persistence-id
-
-Applications can customize a persistent actor's id by specifying an actor name during persistent actor creation as shown in
-section :ref:`event-sourcing-java`. This changes that processor's name in its actor hierarchy and hence influences only
-part of the processor id. To fully customize a processor's id, the ``persistenceId`` method must be overridden.
+A persistent actor must have an identifier that doesn't change across different actor incarnations.
+The identifier must be defined with the ``persistenceId`` method.
 
 .. includecode:: code/docs/persistence/PersistenceDocTest.java#persistence-id-override
 
-Overriding ``persistenceId`` is the recommended way to generate stable identifiers.
 
 .. _recovery-java:
 
@@ -334,13 +326,8 @@ Further possibilities to customize initial recovery are explained in section :re
 Identifiers
 -----------
 
-A persistent view must have an identifier that doesn't change across different actor incarnations. It defaults to the
-``String`` representation of the actor path without the address part and can be obtained via the ``viewId``
-method.
-
-Applications can customize a view's id by specifying an actor name during view creation. This changes that persistent view's
-name in its actor hierarchy and hence influences only part of the view id. To fully customize a view's id, the
-``viewId`` method must be overridden. Overriding ``viewId`` is the recommended way to generate stable identifiers.
+A persistent view must have an identifier that doesn't change across different actor incarnations.
+The identifier must be defined with the ``viewId`` method.
 
 The ``viewId`` must differ from the referenced ``persistenceId``, unless :ref:`snapshots-java` of a view and its
 persistent actor shall be shared (which is what applications usually do not want).

akka-docs/rst/scala/code/docs/persistence/PersistenceDocSpec.scala

@@ -88,6 +88,8 @@ trait PersistenceDocSpec {
     }
 
     class MyProcessor4 extends PersistentActor {
+      override def persistenceId = "my-stable-persistence-id"
+
       //#recovery-completed
 
       def receiveRecover: Receive = {
@@ -310,6 +312,8 @@ trait PersistenceDocSpec {
     class MyPersistentActor(destination: ActorRef) extends PersistentActor {
       val channel = context.actorOf(Channel.props("channel"))
 
+      override def persistenceId = "my-stable-persistence-id"
+
       def handleEvent(event: String) = {
         // update state
         // ...
@@ -338,6 +342,8 @@ trait PersistenceDocSpec {
     //#persist-async
     class MyPersistentActor extends PersistentActor {
 
+      override def persistenceId = "my-stable-persistence-id"
+
       def receiveRecover: Receive = {
         case _ => // handle recovery here
       }
@@ -372,6 +378,8 @@ trait PersistenceDocSpec {
     //#defer
     class MyPersistentActor extends PersistentActor {
 
+      override def persistenceId = "my-stable-persistence-id"
+
       def receiveRecover: Receive = {
         case _ => // handle recovery here
       }

akka-docs/rst/scala/persistence.rst

@@ -100,7 +100,7 @@ is defined by implementing ``receiveRecover`` and ``receiveCommand``. This is de
 .. includecode:: ../../../akka-samples/akka-sample-persistence-scala/src/main/scala/sample/persistence/PersistentActorExample.scala#persistent-actor-example
 
 The example defines two data types, ``Cmd`` and ``Evt`` to represent commands and events, respectively. The
-``state`` of the ``ExampleProcessor`` is a list of persisted event data contained in ``ExampleState``.
+``state`` of the ``ExamplePersistentActor`` is a list of persisted event data contained in ``ExampleState``.
 
 The persistent actor's ``receiveRecover`` method defines how ``state`` is updated during recovery by handling ``Evt``
 and ``SnapshotOffer`` messages. The persistent actor's ``receiveCommand`` method is a command handler. In this example,
@@ -134,20 +134,11 @@ It contains instructions on how to run the ``PersistentActorExample``.
 Identifiers
 -----------
 
-A persistent actor must have an identifier that doesn't change across different actor incarnations. It defaults to the
-``String`` representation of persistent actor's path without the address part and can be obtained via the ``persistenceId``
-method.
-
-.. includecode:: code/docs/persistence/PersistenceDocSpec.scala#persistence-id
-
-Applications can customize a persistent actor's id by specifying an actor name during persistent actor creation as shown in
-section :ref:`event-sourcing`. This changes that persistent actor's name in its actor hierarchy and hence influences only
-part of the persistent actor id. To fully customize a persistent actor's id, the ``persistenceId`` method must be overridden.
+A persistent actor must have an identifier that doesn't change across different actor incarnations.
+The identifier must be defined with the ``persistenceId`` method.
 
 .. includecode:: code/docs/persistence/PersistenceDocSpec.scala#persistence-id-override
 
-Overriding ``persistenceId`` is the recommended way to generate stable identifiers.
-
 .. _recovery:
 
 Recovery
@@ -333,13 +324,8 @@ Further possibilities to customize initial recovery are explained in section :re
 Identifiers
 -----------
 
-A persistent view must have an identifier that doesn't change across different actor incarnations. It defaults to the
-``String`` representation of the actor path without the address part and can be obtained via the ``viewId``
-method.
-
-Applications can customize a view's id by specifying an actor name during view creation. This changes that persistent view's
-name in its actor hierarchy and hence influences only part of the view id. To fully customize a view's id, the
-``viewId`` method must be overridden. Overriding ``viewId`` is the recommended way to generate stable identifiers.
+A persistent view must have an identifier that doesn't change across different actor incarnations.
+The identifier must be defined with the ``viewId`` method.
 
 The ``viewId`` must differ from the referenced ``persistenceId``, unless :ref:`snapshots` of a view and its
 persistent actor shall be shared (which is what applications usually do not want).

akka-persistence/src/main/scala/akka/persistence/Eventsourced.scala

@@ -6,7 +6,7 @@ package akka.persistence
 
 import java.lang.{ Iterable ⇒ JIterable }
 
-import akka.actor.AbstractActor
+import akka.actor.{ AbstractActor, UntypedActor }
 import akka.japi.{ Procedure, Util }
 import akka.persistence.JournalProtocol._
 
@@ -17,7 +17,7 @@ import scala.collection.immutable
  *
  * Event sourcing mixin for a [[Processor]].
  */
-private[persistence] trait Eventsourced extends Processor {
+private[persistence] trait Eventsourced extends ProcessorImpl {
   // TODO consolidate these traits as PersistentActor #15230
 
   /**
@@ -388,23 +388,15 @@ trait EventsourcedProcessor extends Processor with Eventsourced {
 /**
  * An persistent Actor - can be used to implement command or event sourcing.
  */
-// TODO remove EventsourcedProcessor / Processor #15230
-trait PersistentActor extends EventsourcedProcessor
+trait PersistentActor extends ProcessorImpl with Eventsourced {
+  def receive = receiveCommand
+}
 
 /**
  * Java API: an persistent actor - can be used to implement command or event sourcing.
  */
-abstract class UntypedPersistentActor extends UntypedEventsourcedProcessor
-/**
- * Java API: an persistent actor - can be used to implement command or event sourcing.
- */
-abstract class AbstractPersistentActor extends AbstractEventsourcedProcessor
+abstract class UntypedPersistentActor extends UntypedActor with ProcessorImpl with Eventsourced {
 
-/**
- * Java API: an event sourced processor.
- */
-@deprecated("UntypedEventsourcedProcessor will be removed in 2.4.x, instead extend the API equivalent `akka.persistence.PersistentProcessor`", since = "2.3.4")
-abstract class UntypedEventsourcedProcessor extends UntypedProcessor with Eventsourced {
   final def onReceive(message: Any) = onReceiveCommand(message)
 
   final def receiveRecover: Receive = {
@@ -558,16 +550,10 @@ abstract class UntypedEventsourcedProcessor extends UntypedProcessor with Events
 }
 
 /**
- * Java API: compatible with lambda expressions (to be used with [[akka.japi.pf.ReceiveBuilder]]):
- * command handler. Typically validates commands against current state (and/or by
- * communication with other actors). On successful validation, one or more events are
- * derived from a command and these events are then persisted by calling `persist`.
- * Commands sent to event sourced processors must not be [[Persistent]] or
- * [[PersistentBatch]] messages. In this case an `UnsupportedOperationException` is
- * thrown by the processor.
+ * Java API: an persistent actor - can be used to implement command or event sourcing.
  */
-@deprecated("AbstractEventsourcedProcessor will be removed in 2.4.x, instead extend the API equivalent `akka.persistence.PersistentProcessor`", since = "2.3.4")
-abstract class AbstractEventsourcedProcessor extends AbstractActor with EventsourcedProcessor {
+abstract class AbstractPersistentActor extends AbstractActor with PersistentActor with Eventsourced {
+
   /**
    * Java API: asynchronously persists `event`. On successful persistence, `handler` is called with the
    * persisted event. It is guaranteed that no new commands will be received by a processor
@@ -676,9 +662,28 @@ abstract class AbstractEventsourcedProcessor extends AbstractActor with Eventsou
   final def persistAsync[A](events: JIterable[A], handler: Procedure[A]): Unit =
     persistAsync(Util.immutableSeq(events))(event ⇒ handler(event))
 
-  override def receive = super[EventsourcedProcessor].receive
+  override def receive = super[PersistentActor].receive
 
-  override def receive(receive: Receive): Unit = {
-    throw new IllegalArgumentException("Define the behavior by overriding receiveRecover and receiveCommand")
-  }
 }
+
+/**
+ * Java API: an event sourced processor.
+ */
+@deprecated("UntypedEventsourcedProcessor will be removed in 2.4.x, instead extend the API equivalent `akka.persistence.PersistentProcessor`", since = "2.3.4")
+abstract class UntypedEventsourcedProcessor extends UntypedPersistentActor {
+  override def persistenceId: String = processorId
+}
+
+/**
+ * Java API: compatible with lambda expressions (to be used with [[akka.japi.pf.ReceiveBuilder]]):
+ * command handler. Typically validates commands against current state (and/or by
+ * communication with other actors). On successful validation, one or more events are
+ * derived from a command and these events are then persisted by calling `persist`.
+ * Commands sent to event sourced processors must not be [[Persistent]] or
+ * [[PersistentBatch]] messages. In this case an `UnsupportedOperationException` is
+ * thrown by the processor.
+ */
+@deprecated("AbstractEventsourcedProcessor will be removed in 2.4.x, instead extend the API equivalent `akka.persistence.PersistentProcessor`", since = "2.3.4")
+abstract class AbstractEventsourcedProcessor extends AbstractPersistentActor {
+  override def persistenceId: String = processorId
+}

akka-persistence/src/main/scala/akka/persistence/Processor.scala

@@ -52,8 +52,17 @@ import akka.dispatch._
  * @see [[PersistentBatch]]
  */
 @deprecated("Processor will be removed. Instead extend `akka.persistence.PersistentActor` and use it's `persistAsync(command)(callback)` method to get equivalent semantics.", since = "2.3.4")
-trait Processor extends Actor with Recovery {
-  // todo remove Processor in favor of PersistentActor #15230
+trait Processor extends ProcessorImpl {
+  /**
+   * Persistence id. Defaults to this persistent-actors's path and can be overridden.
+   */
+  override def persistenceId: String = processorId
+}
+
+/** INTERNAL API */
+@deprecated("Processor will be removed. Instead extend `akka.persistence.PersistentActor` and use it's `persistAsync(command)(callback)` method to get equivalent semantics.", since = "2.3.4")
+private[akka] trait ProcessorImpl extends Actor with Recovery {
+  // TODO: remove Processor in favor of PersistentActor #15230
 
   import JournalProtocol._
 
@@ -168,11 +177,6 @@ trait Processor extends Actor with Recovery {
   @deprecated("Override `persistenceId: String` instead. Processor will be removed.", since = "2.3.4")
   override def processorId: String = _persistenceId // TODO: remove processorId
 
-  /**
-   * Persistence id. Defaults to this persistent-actors's path and can be overridden.
-   */
-  override def persistenceId: String = processorId
-
   /**
    * Returns `persistenceId`.
    */

akka-samples/akka-sample-persistence-java-lambda/src/main/java/doc/LambdaPersistenceDocTest.java

@@ -138,6 +138,10 @@ public class LambdaPersistenceDocTest {
     //#recovery-completed
     class MyPersistentActor5 extends AbstractPersistentActor {
 
+      @Override public String persistenceId() { 
+        return "my-stable-persistence-id";
+      }
+
       @Override public PartialFunction<Object, BoxedUnit> receiveRecover() {
         return ReceiveBuilder.
           match(String.class, this::handleEvent).build();
@@ -374,6 +378,10 @@ public class LambdaPersistenceDocTest {
         this.channel = context().actorOf(Channel.props(), "channel");
       }
 
+      @Override public String persistenceId() { 
+        return "my-stable-persistence-id";
+      }
+
       private void handleEvent(String event) {
         // update state
         // ...
@@ -401,6 +409,10 @@ public class LambdaPersistenceDocTest {
     //#persist-async
     class MyPersistentActor extends AbstractPersistentActor {
 
+      @Override public String persistenceId() { 
+        return "my-stable-persistence-id";
+      }
+
       private void handleCommand(String c) {
         sender().tell(c, self());
 
@@ -447,6 +459,10 @@ public class LambdaPersistenceDocTest {
     //#defer
     class MyPersistentActor extends AbstractPersistentActor {
 
+      @Override public String persistenceId() { 
+        return "my-stable-persistence-id";
+      }
+
       private void handleCommand(String c) {
         persistAsync(String.format("evt-%s-1", c), e -> {
           sender().tell(e, self());

akka-samples/akka-sample-persistence-java-lambda/src/main/java/sample/persistence/PersistentActorExample.java

@@ -74,12 +74,16 @@ class ExampleState implements Serializable {
 }
 
 class ExamplePersistentActor extends AbstractPersistentActor {
+
     private ExampleState state = new ExampleState();
 
     public int getNumEvents() {
         return state.size();
     }
 
+    @Override
+    public String persistenceId() { return "sample-id-1"; }
+
     @Override
     public PartialFunction<Object, BoxedUnit> receiveRecover() {
         return ReceiveBuilder.

akka-samples/akka-sample-persistence-java-lambda/src/main/java/sample/persistence/PersistentActorFailureExample.java

@@ -18,6 +18,9 @@ public class PersistentActorFailureExample {
   public static class ExamplePersistentActor extends AbstractPersistentActor {
     private ArrayList<Object> received = new ArrayList<Object>();
 
+    @Override
+    public String persistenceId() { return "sample-id-2"; }
+
     @Override
     public PartialFunction<Object, BoxedUnit> receiveCommand() {
       return ReceiveBuilder.

akka-samples/akka-sample-persistence-java-lambda/src/main/java/sample/persistence/ProcessorChannelExample.java

@@ -1,58 +0,0 @@
-/**
- * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
- */
-
-package sample.persistence;
-
-import akka.actor.AbstractActor;
-import akka.actor.ActorRef;
-import akka.actor.ActorSystem;
-import akka.actor.Props;
-import akka.japi.pf.ReceiveBuilder;
-import akka.persistence.*;
-import scala.PartialFunction;
-import scala.runtime.BoxedUnit;
-
-public class ProcessorChannelExample {
-  public static class ExamplePersistentActor extends AbstractProcessor {
-    private ActorRef destination;
-    private ActorRef channel;
-
-    public ExamplePersistentActor(ActorRef destination) {
-      this.destination = destination;
-      this.channel = context().actorOf(Channel.props(), "channel");
-
-      receive(ReceiveBuilder.
-        match(Persistent.class, p -> {
-          System.out.println("processed " + p.payload());
-          channel.tell(Deliver.create(p.withPayload("processed " + p.payload()), destination.path()), self());
-        }).
-        match(String.class, s -> System.out.println("reply = " + s)).build()
-      );
-    }
-  }
-
-  public static class ExampleDestination extends AbstractActor {
-    public ExampleDestination() {
-      receive(ReceiveBuilder.
-        match(ConfirmablePersistent.class, cp -> {
-          System.out.println("received " + cp.payload());
-          sender().tell(String.format("re: %s (%d)", cp.payload(), cp.sequenceNr()), null);
-          cp.confirm();
-        }).build()
-      );
-    }
-  }
-
-  public static void main(String... args) throws Exception {
-    final ActorSystem system = ActorSystem.create("example");
-    final ActorRef destination = system.actorOf(Props.create(ExampleDestination.class));
-    final ActorRef processor = system.actorOf(Props.create(ExamplePersistentActor.class, destination), "processor-1");
-
-    processor.tell(Persistent.create("a"), null);
-    processor.tell(Persistent.create("b"), null);
-
-    Thread.sleep(1000);
-    system.shutdown();
-  }
-}

akka-samples/akka-sample-persistence-java-lambda/src/main/java/sample/persistence/SnapshotExample.java

@@ -62,6 +62,9 @@ public class SnapshotExample {
         build();
     }
 
+    @Override
+    public String persistenceId() { return "sample-id-3"; }
+
     @Override
     public PartialFunction<Object, BoxedUnit> receiveRecover() {
       return ReceiveBuilder.

akka-samples/akka-sample-persistence-java-lambda/src/main/java/sample/persistence/ViewExample.java

@@ -21,9 +21,7 @@ public class ViewExample {
     private int count = 1;
 
     @Override
-    public String persistenceId() {
-      return "persistentActor-5";
-    }
+    public String persistenceId() { return "sample-id-4"; }
 
     @Override
     public PartialFunction<Object, BoxedUnit> receiveCommand() {
@@ -49,10 +47,8 @@ public class ViewExample {
 
     private int numReplicated = 0;
 
-    @Override public String persistenceId() { return "persistentActor-5"; }
-    @Override public String viewId() {
-      return "view-5";
-    }
+    @Override public String persistenceId() { return "sample-id-4"; }
+    @Override public String viewId() { return "sample-view-id-4"; }
 
     public ExampleView() {
       receive(ReceiveBuilder.

akka-samples/akka-sample-persistence-java/src/main/java/sample/persistence/PersistentActorExample.java

@@ -66,6 +66,9 @@ class ExampleState implements Serializable {
 }
 
 class ExamplePersistentActor extends UntypedPersistentActor {
+    @Override
+    public String persistenceId() { return "sample-id-1"; }
+
     private ExampleState state = new ExampleState();
 
     public int getNumEvents() {

akka-samples/akka-sample-persistence-java/src/main/java/sample/persistence/PersistentActorFailureExample.java

@@ -1,12 +1,18 @@
 package sample.persistence;
 
-import java.util.ArrayList;
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
 import akka.japi.Procedure;
-import akka.actor.*;
-import akka.persistence.*;
+import akka.persistence.UntypedPersistentActor;
+
+import java.util.ArrayList;
 
 public class PersistentActorFailureExample {
   public static class ExamplePersistentActor extends UntypedPersistentActor {
+    @Override
+    public String persistenceId() { return "sample-id-2"; }
+
     private ArrayList<Object> received = new ArrayList<Object>();
 
     @Override
@@ -35,7 +41,6 @@ public class PersistentActorFailureExample {
         unhandled(message);
       }
     }
-
   }
 
   public static void main(String... args) throws Exception {

akka-samples/akka-sample-persistence-java/src/main/java/sample/persistence/PersistentViewExample.java

@@ -13,13 +13,11 @@ import java.util.concurrent.TimeUnit;
 
 public class PersistentViewExample {
     public static class ExamplePersistentActor extends UntypedPersistentActor {
-        private int count = 1;
-      
         @Override
-        public String persistenceId() {
-            return "persistentActor-5";
-        }
-        
+        public String persistenceId() { return "sample-id-4"; }
+
+        private int count = 1;
+
         @Override
         public void onReceiveRecover(Object message) {
           if (message instanceof String) {
@@ -49,8 +47,8 @@ public class PersistentViewExample {
 
         private int numReplicated = 0;
 
-        @Override public String persistenceId() { return "persistentActor-5"; }
-        @Override public String viewId() { return "view-5"; }
+        @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 {

akka-samples/akka-sample-persistence-java/src/main/java/sample/persistence/SnapshotExample.java

@@ -1,12 +1,17 @@
 package sample.persistence;
 
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.japi.Procedure;
+import akka.persistence.SaveSnapshotFailure;
+import akka.persistence.SaveSnapshotSuccess;
+import akka.persistence.SnapshotOffer;
+import akka.persistence.UntypedPersistentActor;
+
 import java.io.Serializable;
 import java.util.ArrayList;
 
-import akka.actor.*;
-import akka.persistence.*;
-import akka.japi.Procedure;
-
 public class SnapshotExample {
     public static class ExampleState implements Serializable {
         private final ArrayList<String> received;
@@ -34,6 +39,9 @@ public class SnapshotExample {
     }
 
     public static class ExamplePersistentActor extends UntypedPersistentActor {
+        @Override
+        public String persistenceId() { return "sample-id-3"; }
+
         private ExampleState state = new ExampleState();
 
         @Override
@@ -72,6 +80,7 @@ public class SnapshotExample {
             unhandled(message);
           }
         }
+
     }
 
     public static void main(String... args) throws Exception {

akka-samples/akka-sample-persistence-scala/src/main/scala/sample/persistence/PersistentActorExample.scala

@@ -4,20 +4,22 @@ package sample.persistence
 import akka.actor._
 import akka.persistence._
 
-final case class Cmd(data: String)
-final case class Evt(data: String)
+case class Cmd(data: String)
+case class Evt(data: String)
 
-final case class ExampleState(events: List[String] = Nil) {
-  def update(evt: Evt) = copy(evt.data :: events)
-  def size = events.length
+case class ExampleState(events: List[String] = Nil) {
+  def updated(evt: Evt): ExampleState = copy(evt.data :: events)
+  def size: Int = events.length
   override def toString: String = events.reverse.toString
 }
 
-class ExampleProcessor extends PersistentActor {
+class ExamplePersistentActor extends PersistentActor {
+  override def persistenceId = "sample-id-1"
+
   var state = ExampleState()
 
   def updateState(event: Evt): Unit =
-    state = state.update(event)
+    state = state.updated(event)
 
   def numEvents =
     state.size
@@ -44,14 +46,14 @@ class ExampleProcessor extends PersistentActor {
 object PersistentActorExample extends App {
 
   val system = ActorSystem("example")
-  val processor = system.actorOf(Props[ExampleProcessor], "processor-4-scala")
+  val persistentActor = system.actorOf(Props[ExamplePersistentActor], "persistentActor-4-scala")
 
-  processor ! Cmd("foo")
-  processor ! Cmd("baz")
-  processor ! Cmd("bar")
-  processor ! "snap"
-  processor ! Cmd("buzz")
-  processor ! "print"
+  persistentActor ! Cmd("foo")
+  persistentActor ! Cmd("baz")
+  persistentActor ! Cmd("bar")
+  persistentActor ! "snap"
+  persistentActor ! Cmd("buzz")
+  persistentActor ! "print"
 
   Thread.sleep(1000)
   system.shutdown()

akka-samples/akka-sample-persistence-scala/src/main/scala/sample/persistence/PersistentActorFailureExample.scala

@@ -5,6 +5,8 @@ import akka.persistence._
 
 object PersistentActorFailureExample extends App {
   class ExamplePersistentActor extends PersistentActor {
+    override def persistenceId = "sample-id-2"
+
     var received: List[String] = Nil // state
 
     def receiveCommand: Actor.Receive = {

akka-samples/akka-sample-persistence-scala/src/main/scala/sample/persistence/SnapshotExample.scala

@@ -10,6 +10,8 @@ object SnapshotExample extends App {
   }
 
   class ExamplePersistentActor extends PersistentActor {
+    def persistenceId: String = "sample-id-3"
+
     var state = ExampleState()
 
     def receiveCommand: Actor.Receive = {
@@ -28,6 +30,7 @@ object SnapshotExample extends App {
       case evt: String =>
         state = state.updated(evt)
     }
+
   }
 
   val system = ActorSystem("example")

akka-samples/akka-sample-persistence-scala/src/main/scala/sample/persistence/ViewExample.scala

@@ -7,7 +7,7 @@ import akka.persistence._
 
 object ViewExample extends App {
   class ExamplePersistentActor extends PersistentActor {
-    override def persistenceId = "persistentActor-5"
+    override def persistenceId = "sample-id-4"
 
     var count = 1
 
@@ -27,8 +27,8 @@ object ViewExample extends App {
   class ExampleView extends PersistentView {
     private var numReplicated = 0
 
-    override def persistenceId: String = "persistentActor-5"
-    override def viewId = "view-5"
+    override def persistenceId: String = "sample-id-4"
+    override def viewId = "sample-view-id-4"
 
     def receive = {
       case "snap" =>