Remove samples (#22288)

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

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

@@ -0,0 +1,130 @@
+/**
+ * Copyright (C) 2009-2017 Lightbend Inc. <http://www.lightbend.com>
+ */
+
+package docs.persistence;
+
+//#persistent-actor-example
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.persistence.AbstractPersistentActor;
+import akka.persistence.SnapshotOffer;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+
+import static java.util.Arrays.asList;
+
+class Cmd implements Serializable {
+    private static final long serialVersionUID = 1L;
+    private final String data;
+
+    public Cmd(String data) {
+        this.data = data;
+    }
+
+    public String getData() {
+        return data;
+    }
+}
+
+class Evt implements Serializable {
+    private static final long serialVersionUID = 1L;
+    private final String data;
+
+    public Evt(String data) {
+        this.data = data;
+    }
+
+    public String getData() {
+        return data;
+    }
+}
+
+class ExampleState implements Serializable {
+    private static final long serialVersionUID = 1L;
+    private final ArrayList<String> events;
+
+    public ExampleState() {
+        this(new ArrayList<>());
+    }
+
+    public ExampleState(ArrayList<String> events) {
+        this.events = events;
+    }
+
+    public ExampleState copy() {
+        return new ExampleState(new ArrayList<>(events));
+    }
+
+    public void update(Evt evt) {
+        events.add(evt.getData());
+    }
+
+    public int size() {
+        return events.size();
+    }
+
+    @Override
+    public String toString() {
+        return events.toString();
+    }
+}
+
+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 Receive createReceiveRecover() {
+        return receiveBuilder()
+            .match(Evt.class, state::update)
+            .match(SnapshotOffer.class, ss -> state = (ExampleState) ss.snapshot())
+            .build();
+    }
+
+    @Override
+    public Receive createReceive() {
+        return receiveBuilder()
+            .match(Cmd.class, c -> {
+              final String data = c.getData();
+              final Evt evt1 = new Evt(data + "-" + getNumEvents());
+              final Evt evt2 = new Evt(data + "-" + (getNumEvents() + 1));
+              persistAll(asList(evt1, evt2), (Evt evt) -> {
+                state.update(evt);
+                if (evt.equals(evt2)) {
+                  getContext().system().eventStream().publish(evt);
+                }
+              });
+            })
+            .matchEquals("snap", s -> saveSnapshot(state.copy()))
+            .matchEquals("print", s -> System.out.println(state))
+            .build();
+    }
+}
+//#persistent-actor-example
+
+public class PersistentActorExample {
+    public static void main(String... args) throws Exception {
+        final ActorSystem system = ActorSystem.create("example");
+        final ActorRef persistentActor = system.actorOf(Props.create(ExamplePersistentActor.class), "persistentActor-4-java8");
+        persistentActor.tell(new Cmd("foo"), null);
+        persistentActor.tell(new Cmd("baz"), null);
+        persistentActor.tell(new Cmd("bar"), null);
+        persistentActor.tell("snap", null);
+        persistentActor.tell(new Cmd("buzz"), null);
+        persistentActor.tell("print", null);
+
+        Thread.sleep(10000);
+        system.terminate();
+    }
+}