Convert UntypedActor to AbstractActor #22308

akka-camel/src/test/java/akka/camel/CustomRouteTest.java

@@ -28,8 +28,11 @@ public class CustomRouteTest extends JUnitSuite {
   private ActorSystem system = null;
   private Camel camel = null;
 
-  public static class MyActor extends UntypedActor {
-    @Override public void onReceive(Object o) {}
+  public static class MyActor extends AbstractActor {
+    @Override
+    public Receive createReceive() {
+      return receiveBuilder().build();
+    }
   }
 
   @Before

akka-docs/rst/java/code/docs/cluster/FactorialBackend.java

@@ -1,38 +1,33 @@
 package docs.cluster;
 
 import java.math.BigInteger;
-import java.util.concurrent.Callable;
 import scala.concurrent.Future;
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.dispatch.Mapper;
 import static akka.dispatch.Futures.future;
 import static akka.pattern.Patterns.pipe;
 
 //#backend
-public class FactorialBackend extends UntypedActor {
+public class FactorialBackend extends AbstractActor {
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof Integer) {
-      final Integer n = (Integer) message;
-      Future<BigInteger> f = future(new Callable<BigInteger>() {
-        public BigInteger call() {
-          return factorial(n);
-        }
-      }, getContext().dispatcher());
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(Integer.class, n -> {
+        Future<BigInteger> f = future(() -> factorial(n),
+          getContext().dispatcher());
 
-      Future<FactorialResult> result = f.map(
+        Future<FactorialResult> result = f.map(
           new Mapper<BigInteger, FactorialResult>() {
             public FactorialResult apply(BigInteger factorial) {
               return new FactorialResult(n, factorial);
             }
           }, getContext().dispatcher());
 
-      pipe(result, getContext().dispatcher()).to(getSender());
+        pipe(result, getContext().dispatcher()).to(sender());
 
-    } else {
-      unhandled(message);
-    }
+      })
+      .build();
   }
 
   BigInteger factorial(int n) {

akka-docs/rst/java/code/docs/cluster/FactorialFrontend.java

@@ -13,18 +13,16 @@ import akka.cluster.routing.ClusterRouterGroup;
 import akka.cluster.routing.ClusterRouterGroupSettings;
 import akka.cluster.routing.ClusterRouterPool;
 import akka.cluster.routing.ClusterRouterPoolSettings;
-import akka.routing.ConsistentHashingGroup;
-import akka.routing.ConsistentHashingPool;
 import scala.concurrent.duration.Duration;
 import akka.actor.ActorRef;
 import akka.actor.ReceiveTimeout;
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.event.Logging;
 import akka.event.LoggingAdapter;
 import akka.routing.FromConfig;
 
 //#frontend
-public class FactorialFrontend extends UntypedActor {
+public class FactorialFrontend extends AbstractActor {
   final int upToN;
   final boolean repeat;
 
@@ -45,30 +43,28 @@ public class FactorialFrontend extends UntypedActor {
   }
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof FactorialResult) {
-      FactorialResult result = (FactorialResult) message;
-      if (result.n == upToN) {
-        log.debug("{}! = {}", result.n, result.factorial);
-        if (repeat)
-          sendJobs();
-        else
-          getContext().stop(getSelf());
-      }
-
-    } else if (message instanceof ReceiveTimeout) {
-      log.info("Timeout");
-      sendJobs();
-
-    } else {
-      unhandled(message);
-    }
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(FactorialResult.class, result -> {
+        if (result.n == upToN) {
+          log.debug("{}! = {}", result.n, result.factorial);
+          if (repeat)
+            sendJobs();
+          else
+            getContext().stop(self());
+        }
+      })
+      .match(ReceiveTimeout.class, x -> {
+        log.info("Timeout");
+        sendJobs();
+      })
+      .build();
   }
 
   void sendJobs() {
     log.info("Starting batch of factorials up to [{}]", upToN);
     for (int n = 1; n <= upToN; n++) {
-      backend.tell(n, getSelf());
+      backend.tell(n, self());
     }
   }
 
@@ -76,7 +72,7 @@ public class FactorialFrontend extends UntypedActor {
 //#frontend
 
 //not used, only for documentation
-abstract class FactorialFrontend2 extends UntypedActor {
+abstract class FactorialFrontend2 extends AbstractActor {
   //#router-lookup-in-code
   int totalInstances = 100;
   Iterable<String> routeesPaths = Arrays.asList("/user/factorialBackend", "");
@@ -91,7 +87,7 @@ abstract class FactorialFrontend2 extends UntypedActor {
 }
 
 //not used, only for documentation
-abstract class FactorialFrontend3 extends UntypedActor {
+abstract class FactorialFrontend3 extends AbstractActor {
   //#router-deploy-in-code
   int totalInstances = 100;
   int maxInstancesPerNode = 3;

akka-docs/rst/java/code/docs/cluster/MetricsListener.java

@@ -1,7 +1,7 @@
 package docs.cluster;
 
 //#metrics-listener
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.cluster.Cluster;
 import akka.cluster.ClusterEvent.CurrentClusterState;
 import akka.cluster.metrics.ClusterMetricsChanged;
@@ -13,7 +13,7 @@ import akka.cluster.metrics.ClusterMetricsExtension;
 import akka.event.Logging;
 import akka.event.LoggingAdapter;
 
-public class MetricsListener extends UntypedActor {
+public class MetricsListener extends AbstractActor {
   LoggingAdapter log = Logging.getLogger(getContext().system(), this);
 
   Cluster cluster = Cluster.get(getContext().system());
@@ -33,23 +33,21 @@ public class MetricsListener extends UntypedActor {
 	  extension.unsubscribe(getSelf());
   }
 
-
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof ClusterMetricsChanged) {
-    	ClusterMetricsChanged clusterMetrics = (ClusterMetricsChanged) message;
-      for (NodeMetrics nodeMetrics : clusterMetrics.getNodeMetrics()) {
-        if (nodeMetrics.address().equals(cluster.selfAddress())) {
-          logHeap(nodeMetrics);
-          logCpu(nodeMetrics);
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(ClusterMetricsChanged.class, clusterMetrics -> {
+        for (NodeMetrics nodeMetrics : clusterMetrics.getNodeMetrics()) {
+          if (nodeMetrics.address().equals(cluster.selfAddress())) {
+            logHeap(nodeMetrics);
+            logCpu(nodeMetrics);
+          }
         }
-      }
-
-    } else if (message instanceof CurrentClusterState) {
-      // Ignore.
-    } else {
-      unhandled(message);
-    }
+      })
+      .match(CurrentClusterState.class, message -> {
+        // Ignore.
+      })
+      .build();
   }
 
   void logHeap(NodeMetrics nodeMetrics) {

akka-docs/rst/java/code/docs/cluster/SimpleClusterListener.java

@@ -1,6 +1,6 @@
 package docs.cluster;
 
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.cluster.Cluster;
 import akka.cluster.ClusterEvent;
 import akka.cluster.ClusterEvent.MemberEvent;
@@ -10,7 +10,7 @@ import akka.cluster.ClusterEvent.UnreachableMember;
 import akka.event.Logging;
 import akka.event.LoggingAdapter;
 
-public class SimpleClusterListener extends UntypedActor {
+public class SimpleClusterListener extends AbstractActor {
   LoggingAdapter log = Logging.getLogger(getContext().system(), this);
   Cluster cluster = Cluster.get(getContext().system());
 
@@ -30,25 +30,20 @@ public class SimpleClusterListener extends UntypedActor {
   }
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof MemberUp) {
-      MemberUp mUp = (MemberUp) message;
-      log.info("Member is Up: {}", mUp.member());
-
-    } else if (message instanceof UnreachableMember) {
-      UnreachableMember mUnreachable = (UnreachableMember) message;
-      log.info("Member detected as unreachable: {}", mUnreachable.member());
-
-    } else if (message instanceof MemberRemoved) {
-      MemberRemoved mRemoved = (MemberRemoved) message;
-      log.info("Member is Removed: {}", mRemoved.member());
-
-    } else if (message instanceof MemberEvent) {
-      // ignore
-
-    } else {
-      unhandled(message);
-    }
-
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(MemberUp.class, mUp -> {
+        log.info("Member is Up: {}", mUp.member());
+      })
+      .match(UnreachableMember.class, mUnreachable -> {
+        log.info("Member detected as unreachable: {}", mUnreachable.member());
+      })
+      .match(MemberRemoved.class, mRemoved -> {
+        log.info("Member is Removed: {}", mRemoved.member());
+      })
+      .match(MemberEvent.class, message -> {
+        // ignore
+      })
+      .build();
   }
 }

akka-docs/rst/java/code/docs/cluster/SimpleClusterListener2.java

@@ -1,6 +1,6 @@
 package docs.cluster;
 
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.cluster.Cluster;
 import akka.cluster.ClusterEvent.CurrentClusterState;
 import akka.cluster.ClusterEvent.MemberEvent;
@@ -10,7 +10,7 @@ import akka.cluster.ClusterEvent.UnreachableMember;
 import akka.event.Logging;
 import akka.event.LoggingAdapter;
 
-public class SimpleClusterListener2 extends UntypedActor {
+public class SimpleClusterListener2 extends AbstractActor {
   LoggingAdapter log = Logging.getLogger(getContext().system(), this);
   Cluster cluster = Cluster.get(getContext().system());
 
@@ -29,29 +29,23 @@ public class SimpleClusterListener2 extends UntypedActor {
   }
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof CurrentClusterState) {
-      CurrentClusterState state = (CurrentClusterState) message;
-      log.info("Current members: {}", state.members());
-
-    } else if (message instanceof MemberUp) {
-      MemberUp mUp = (MemberUp) message;
-      log.info("Member is Up: {}", mUp.member());
-
-    } else if (message instanceof UnreachableMember) {
-      UnreachableMember mUnreachable = (UnreachableMember) message;
-      log.info("Member detected as unreachable: {}", mUnreachable.member());
-
-    } else if (message instanceof MemberRemoved) {
-      MemberRemoved mRemoved = (MemberRemoved) message;
-      log.info("Member is Removed: {}", mRemoved.member());
-
-    } else if (message instanceof MemberEvent) {
-      // ignore
-
-    } else {
-      unhandled(message);
-    }
-
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(CurrentClusterState.class, state -> {
+        log.info("Current members: {}", state.members());
+      })
+      .match(MemberUp.class, mUp -> {
+        log.info("Member is Up: {}", mUp.member());
+      })
+      .match(UnreachableMember.class, mUnreachable -> {
+        log.info("Member detected as unreachable: {}", mUnreachable.member());
+      })
+      .match(MemberRemoved.class, mRemoved -> {
+        log.info("Member is Removed: {}", mRemoved.member());
+      })
+      .match(MemberEvent.class, event -> {
+        // ignore
+      })
+      .build();
   }
 }

akka-docs/rst/java/code/docs/cluster/StatsAggregator.java

@@ -9,10 +9,10 @@ import docs.cluster.StatsMessages.StatsResult;
 import scala.concurrent.duration.Duration;
 import akka.actor.ActorRef;
 import akka.actor.ReceiveTimeout;
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 
 //#aggregator
-public class StatsAggregator extends UntypedActor {
+public class StatsAggregator extends AbstractActor {
 
   final int expectedResults;
   final ActorRef replyTo;
@@ -29,27 +29,26 @@ public class StatsAggregator extends UntypedActor {
   }
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof Integer) {
-      Integer wordCount = (Integer) message;
-      results.add(wordCount);
-      if (results.size() == expectedResults) {
-        int sum = 0;
-        for (int c : results)
-          sum += c;
-        double meanWordLength = ((double) sum) / results.size();
-        replyTo.tell(new StatsResult(meanWordLength), getSelf());
-        getContext().stop(getSelf());
-      }
-
-    } else if (message == ReceiveTimeout.getInstance()) {
-      replyTo.tell(new JobFailed("Service unavailable, try again later"),
-          getSelf());
-      getContext().stop(getSelf());
-
-    } else {
-      unhandled(message);
-    }
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(Integer.class, wordCount -> {
+        results.add(wordCount);
+        if (results.size() == expectedResults) {
+          int sum = 0;
+          for (int c : results) {
+            sum += c;
+          }
+          double meanWordLength = ((double) sum) / results.size();
+          replyTo.tell(new StatsResult(meanWordLength), self());
+          getContext().stop(self());
+        }
+      })
+      .match(ReceiveTimeout.class, x -> {
+        replyTo.tell(new JobFailed("Service unavailable, try again later"),
+          self());
+        getContext().stop(self());
+      })
+      .build();
   }
 
 }

akka-docs/rst/java/code/docs/cluster/StatsSampleClient.java

@@ -15,7 +15,7 @@ import scala.concurrent.duration.FiniteDuration;
 import akka.actor.ActorSelection;
 import akka.actor.Address;
 import akka.actor.Cancellable;
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.cluster.Cluster;
 import akka.cluster.ClusterEvent.UnreachableMember;
 import akka.cluster.ClusterEvent.ReachableMember;
@@ -26,7 +26,7 @@ import akka.cluster.ClusterEvent.ReachabilityEvent;
 import akka.cluster.Member;
 import akka.cluster.MemberStatus;
 
-public class StatsSampleClient extends UntypedActor {
+public class StatsSampleClient extends AbstractActor {
 
   final String servicePath;
   final Cancellable tickTask;
@@ -40,7 +40,7 @@ public class StatsSampleClient extends UntypedActor {
     tickTask = getContext()
         .system()
         .scheduler()
-        .schedule(interval, interval, getSelf(), "tick",
+        .schedule(interval, interval, self(), "tick",
             getContext().dispatcher(), null);
   }
 
@@ -53,59 +53,48 @@ public class StatsSampleClient extends UntypedActor {
   //re-subscribe when restart
   @Override
   public void postStop() {
-    cluster.unsubscribe(getSelf());
+    cluster.unsubscribe(self());
     tickTask.cancel();
   }
 
   @Override
-  public void onReceive(Object message) {
-    if (message.equals("tick") && !nodes.isEmpty()) {
-      // just pick any one
-      List<Address> nodesList = new ArrayList<Address>(nodes);
-      Address address = nodesList.get(ThreadLocalRandom.current().nextInt(
+  public Receive createReceive() {
+    return receiveBuilder()
+      .matchEquals("tick", x -> !nodes.isEmpty(), x -> {
+        // just pick any one
+        List<Address> nodesList = new ArrayList<Address>(nodes);
+        Address address = nodesList.get(ThreadLocalRandom.current().nextInt(
           nodesList.size()));
-      ActorSelection service = getContext().actorSelection(address + servicePath);
-      service.tell(new StatsJob("this is the text that will be analyzed"),
-          getSelf());
-
-    } else if (message instanceof StatsResult) {
-      StatsResult result = (StatsResult) message;
-      System.out.println(result);
-
-    } else if (message instanceof JobFailed) {
-      JobFailed failed = (JobFailed) message;
-      System.out.println(failed);
-
-    } else if (message instanceof CurrentClusterState) {
-      CurrentClusterState state = (CurrentClusterState) message;
-      nodes.clear();
-      for (Member member : state.getMembers()) {
-        if (member.hasRole("compute") && member.status().equals(MemberStatus.up())) {
-          nodes.add(member.address());
+        ActorSelection service = getContext().actorSelection(address + servicePath);
+        service.tell(new StatsJob("this is the text that will be analyzed"),
+          self());
+      })
+      .match(StatsResult.class, System.out::println)
+      .match(JobFailed.class, System.out::println)
+      .match(CurrentClusterState.class, state -> {
+        nodes.clear();
+        for (Member member : state.getMembers()) {
+          if (member.hasRole("compute") && member.status().equals(MemberStatus.up())) {
+            nodes.add(member.address());
+          }
         }
-      }
+      })
+      .match(MemberUp.class, mUp -> {
+        if (mUp.member().hasRole("compute"))
+          nodes.add(mUp.member().address());
+      })
+      .match(MemberEvent.class, event -> {
+        nodes.remove(event.member().address());
+      })
+      .match(UnreachableMember.class, unreachable -> {
+        nodes.remove(unreachable.member().address());
+      })
+      .match(ReachableMember.class, reachable -> {
+        if (reachable.member().hasRole("compute"))
+          nodes.add(reachable.member().address());
 
-    } else if (message instanceof MemberUp) {
-      MemberUp mUp = (MemberUp) message;
-      if (mUp.member().hasRole("compute"))
-        nodes.add(mUp.member().address());
-
-    } else if (message instanceof MemberEvent) {
-      MemberEvent other = (MemberEvent) message;
-      nodes.remove(other.member().address());
-
-    } else if (message instanceof UnreachableMember) {
-      UnreachableMember unreachable = (UnreachableMember) message;
-      nodes.remove(unreachable.member().address());
-
-    } else if (message instanceof ReachableMember) {
-      ReachableMember reachable = (ReachableMember) message;
-      if (reachable.member().hasRole("compute"))
-        nodes.add(reachable.member().address());
-
-    } else {
-      unhandled(message);
-    }
+      })
+      .build();
   }
 
 }

akka-docs/rst/java/code/docs/cluster/StatsService.java

@@ -9,14 +9,14 @@ import akka.routing.ConsistentHashingPool;
 import docs.cluster.StatsMessages.StatsJob;
 import akka.actor.ActorRef;
 import akka.actor.Props;
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.routing.ConsistentHashingRouter.ConsistentHashableEnvelope;
 import akka.routing.FromConfig;
 
 import java.util.Collections;
 
 //#service
-public class StatsService extends UntypedActor {
+public class StatsService extends AbstractActor {
 
   // This router is used both with lookup and deploy of routees. If you
   // have a router with only lookup of routees you can use Props.empty()
@@ -26,35 +26,30 @@ public class StatsService extends UntypedActor {
       "workerRouter");
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof StatsJob) {
-      StatsJob job = (StatsJob) message;
-      if (job.getText().equals("")) {
-        unhandled(message);
-      } else {
-        final String[] words = job.getText().split(" ");
-        final ActorRef replyTo = getSender();
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(StatsJob.class, job -> !job.getText().isEmpty(), job -> {
+        String[] words = job.getText().split(" ");
+        ActorRef replyTo = sender();
 
         // create actor that collects replies from workers
         ActorRef aggregator = getContext().actorOf(
-            Props.create(StatsAggregator.class, words.length, replyTo));
+          Props.create(StatsAggregator.class, words.length, replyTo));
 
         // send each word to a worker
         for (String word : words) {
           workerRouter.tell(new ConsistentHashableEnvelope(word, word),
-              aggregator);
+            aggregator);
         }
-      }
 
-    } else {
-      unhandled(message);
-    }
+      })
+      .build();
   }
 }
 //#service
 
 //not used, only for documentation
-abstract class StatsService2 extends UntypedActor {
+abstract class StatsService2 extends AbstractActor {
   //#router-lookup-in-code
   int totalInstances = 100;
   Iterable<String> routeesPaths = Collections
@@ -69,7 +64,7 @@ abstract class StatsService2 extends UntypedActor {
 }
 
 //not used, only for documentation
-abstract class StatsService3 extends UntypedActor {
+abstract class StatsService3 extends AbstractActor {
   //#router-deploy-in-code
   int totalInstances = 100;
   int maxInstancesPerNode = 3;

akka-docs/rst/java/code/docs/cluster/StatsWorker.java

@@ -3,28 +3,25 @@ package docs.cluster;
 import java.util.HashMap;
 import java.util.Map;
 
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 
 //#worker
-public class StatsWorker extends UntypedActor {
+public class StatsWorker extends AbstractActor {
 
   Map<String, Integer> cache = new HashMap<String, Integer>();
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof String) {
-      String word = (String) message;
-      Integer length = cache.get(word);
-      if (length == null) {
-        length = word.length();
-        cache.put(word, length);
-      }
-      getSender().tell(length, getSelf());
-
-    } else {
-      unhandled(message);
-    }
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(String.class, word -> {
+        Integer length = cache.get(word);
+        if (length == null) {
+          length = word.length();
+          cache.put(word, length);
+        }
+        sender().tell(length, self());
+      })
+      .build();
   }
-
 }
 //#worker

akka-docs/rst/java/code/docs/cluster/TransformationBackend.java

@@ -3,7 +3,7 @@ package docs.cluster;
 import static docs.cluster.TransformationMessages.BACKEND_REGISTRATION;
 import docs.cluster.TransformationMessages.TransformationJob;
 import docs.cluster.TransformationMessages.TransformationResult;
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 import akka.cluster.Cluster;
 import akka.cluster.ClusterEvent.CurrentClusterState;
 import akka.cluster.ClusterEvent.MemberUp;
@@ -11,50 +11,46 @@ import akka.cluster.Member;
 import akka.cluster.MemberStatus;
 
 //#backend
-public class TransformationBackend extends UntypedActor {
+public class TransformationBackend extends AbstractActor {
 
   Cluster cluster = Cluster.get(getContext().system());
 
   //subscribe to cluster changes, MemberUp
   @Override
   public void preStart() {
-    cluster.subscribe(getSelf(), MemberUp.class);
+    cluster.subscribe(self(), MemberUp.class);
   }
 
   //re-subscribe when restart
   @Override
   public void postStop() {
-    cluster.unsubscribe(getSelf());
+    cluster.unsubscribe(self());
   }
 
   @Override
-  public void onReceive(Object message) {
-    if (message instanceof TransformationJob) {
-      TransformationJob job = (TransformationJob) message;
-      getSender().tell(new TransformationResult(job.getText().toUpperCase()),
-          getSelf());
-
-    } else if (message instanceof CurrentClusterState) {
-      CurrentClusterState state = (CurrentClusterState) message;
-      for (Member member : state.getMembers()) {
-        if (member.status().equals(MemberStatus.up())) {
-          register(member);
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(TransformationJob.class, job -> {
+        sender().tell(new TransformationResult(job.getText().toUpperCase()),
+          self());
+      })
+      .match(CurrentClusterState.class, state -> {
+        for (Member member : state.getMembers()) {
+          if (member.status().equals(MemberStatus.up())) {
+            register(member);
+          }
         }
-      }
-
-    } else if (message instanceof MemberUp) {
-      MemberUp mUp = (MemberUp) message;
-      register(mUp.member());
-
-    } else {
-      unhandled(message);
-    }
+      })
+      .match(MemberUp.class, mUp -> {
+        register(mUp.member());
+      })
+      .build();
   }
 
   void register(Member member) {
     if (member.hasRole("frontend"))
       getContext().actorSelection(member.address() + "/user/frontend").tell(
-          BACKEND_REGISTRATION, getSelf());
+          BACKEND_REGISTRATION, self());
   }
 }
 //#backend

akka-docs/rst/java/code/docs/cluster/TransformationFrontend.java

@@ -9,39 +9,35 @@ import docs.cluster.TransformationMessages.JobFailed;
 import docs.cluster.TransformationMessages.TransformationJob;
 import akka.actor.ActorRef;
 import akka.actor.Terminated;
-import akka.actor.UntypedActor;
+import akka.actor.AbstractActor;
 
 //#frontend
-public class TransformationFrontend extends UntypedActor {
+public class TransformationFrontend extends AbstractActor {
 
   List<ActorRef> backends = new ArrayList<ActorRef>();
   int jobCounter = 0;
 
   @Override
-  public void onReceive(Object message) {
-    if ((message instanceof TransformationJob) && backends.isEmpty()) {
-      TransformationJob job = (TransformationJob) message;
-      getSender().tell(
+  public Receive createReceive() {
+    return receiveBuilder()
+      .match(TransformationJob.class, job -> backends.isEmpty(), job -> {
+        sender().tell(
           new JobFailed("Service unavailable, try again later", job),
-          getSender());
-
-    } else if (message instanceof TransformationJob) {
-      TransformationJob job = (TransformationJob) message;
-      jobCounter++;
-      backends.get(jobCounter % backends.size())
+          sender());
+      })
+      .match(TransformationJob.class, job -> {
+        jobCounter++;
+        backends.get(jobCounter % backends.size())
           .forward(job, getContext());
-
-    } else if (message.equals(BACKEND_REGISTRATION)) {
-      getContext().watch(getSender());
-      backends.add(getSender());
-
-    } else if (message instanceof Terminated) {
-      Terminated terminated = (Terminated) message;
-      backends.remove(terminated.getActor());
-
-    } else {
-      unhandled(message);
-    }
+      })
+      .matchEquals(BACKEND_REGISTRATION, x -> {
+        getContext().watch(sender());
+        backends.add(sender());
+      })
+      .match(Terminated.class, terminated -> {
+        backends.remove(terminated.getActor());
+      })
+      .build();
   }
 
 }

akka-docs/rst/project/migration-guide-2.4.x-2.5.x.rst

@@ -167,7 +167,7 @@ New::
   }
 
 It's recommended to migrate ``UntypedActor`` to ``AbstractActor`` by implementing
-``createReceive`` instead of ``onMessage``.
+``createReceive`` instead of ``onReceive``.
 
 Old::