Remove samples (#22288)

Add code, that was used for documentation to the appropriate projects
or akka-docs.

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

@@ -0,0 +1,56 @@
+package docs.cluster;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import docs.cluster.StatsMessages.JobFailed;
+import docs.cluster.StatsMessages.StatsResult;
+import scala.concurrent.duration.Duration;
+import akka.actor.ActorRef;
+import akka.actor.ReceiveTimeout;
+import akka.actor.UntypedActor;
+
+//#aggregator
+public class StatsAggregator extends UntypedActor {
+
+  final int expectedResults;
+  final ActorRef replyTo;
+  final List<Integer> results = new ArrayList<Integer>();
+
+  public StatsAggregator(int expectedResults, ActorRef replyTo) {
+    this.expectedResults = expectedResults;
+    this.replyTo = replyTo;
+  }
+
+  @Override
+  public void preStart() {
+    getContext().setReceiveTimeout(Duration.create(3, TimeUnit.SECONDS));
+  }
+
+  @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);
+    }
+  }
+
+}
+//#aggregator