/**
* Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
*/
package docs.event;
import akka.event.japi.EventBus;
import java.util.concurrent.TimeUnit;
import org.junit.ClassRule;
import org.junit.Test;
import akka.actor.ActorSystem;
import akka.actor.ActorRef;
import akka.event.japi.*;
import akka.testkit.AkkaJUnitActorSystemResource;
import akka.testkit.JavaTestKit;
import akka.event.japi.EventBus;
import akka.util.Subclassification;
import org.junit.ClassRule;
import org.junit.Test;
import scala.concurrent.duration.FiniteDuration;
//#lookup-bus
import akka.event.japi.LookupEventBus;
import java.util.concurrent.TimeUnit;
//#lookup-bus
//#subchannel-bus
import akka.event.japi.SubchannelEventBus;
import akka.util.Subclassification;
//#subchannel-bus
//#scanning-bus
import akka.event.japi.ScanningEventBus;
//#scanning-bus
//#actor-bus
import akka.event.japi.ActorEventBus;
//#actor-bus
public class EventBusDocTest {
public static class Event {}
public static class Subscriber {}
public static class Classifier {}
static public interface EventBusApi extends EventBus<Event, Subscriber, Classifier> {
@Override
//#event-bus-api
/**
* Attempts to register the subscriber to the specified Classifier
* @return true if successful and false if not (because it was already
* subscribed to that Classifier, or otherwise)
*/
public boolean subscribe(Subscriber subscriber, Classifier to);
//#event-bus-api
@Override
//#event-bus-api
/**
* Attempts to deregister the subscriber from the specified Classifier
* @return true if successful and false if not (because it wasn't subscribed
* to that Classifier, or otherwise)
*/
public boolean unsubscribe(Subscriber subscriber, Classifier from);
//#event-bus-api
@Override
//#event-bus-api
/**
* Attempts to deregister the subscriber from all Classifiers it may be subscribed to
*/
public void unsubscribe(Subscriber subscriber);
//#event-bus-api
@Override
//#event-bus-api
/**
* Publishes the specified Event to this bus
*/
public void publish(Event event);
//#event-bus-api
}
static
//#lookup-bus
public class MsgEnvelope {
public final String topic;
public final Object payload;
public MsgEnvelope(String topic, Object payload) {
this.topic = topic;
this.payload = payload;
}
}
//#lookup-bus
static
//#lookup-bus
/**
* Publishes the payload of the MsgEnvelope when the topic of the
* MsgEnvelope equals the String specified when subscribing.
*/
public class LookupBusImpl extends LookupEventBus<MsgEnvelope, ActorRef, String> {
// is used for extracting the classifier from the incoming events
@Override public String classify(MsgEnvelope event) {
return event.topic;
}
// will be invoked for each event for all subscribers which registered themselves
// for the event’s classifier
@Override public void publish(MsgEnvelope event, ActorRef subscriber) {
subscriber.tell(event.payload, ActorRef.noSender());
}
// must define a full order over the subscribers, expressed as expected from
// `java.lang.Comparable.compare`
@Override public int compareSubscribers(ActorRef a, ActorRef b) {
return a.compareTo(b);
}
// determines the initial size of the index data structure
// used internally (i.e. the expected number of different classifiers)
@Override public int mapSize() {
return 128;
}
}
//#lookup-bus
static
//#subchannel-bus
public class StartsWithSubclassification implements Subclassification<String> {
@Override public boolean isEqual(String x, String y) {
return x.equals(y);
}
@Override public boolean isSubclass(String x, String y) {
return x.startsWith(y);
}
}
//#subchannel-bus
static
//#subchannel-bus
/**
* Publishes the payload of the MsgEnvelope when the topic of the
* MsgEnvelope starts with the String specified when subscribing.
*/
public class SubchannelBusImpl extends SubchannelEventBus<MsgEnvelope, ActorRef, String> {
// Subclassification is an object providing `isEqual` and `isSubclass`
// to be consumed by the other methods of this classifier
@Override public Subclassification<String> subclassification() {
return new StartsWithSubclassification();
}
// is used for extracting the classifier from the incoming events
@Override public String classify(MsgEnvelope event) {
return event.topic;
}
// will be invoked for each event for all subscribers which registered themselves
// for the event’s classifier
@Override public void publish(MsgEnvelope event, ActorRef subscriber) {
subscriber.tell(event.payload, ActorRef.noSender());
}
}
//#subchannel-bus
static
//#scanning-bus
/**
* Publishes String messages with length less than or equal to the length
* specified when subscribing.
*/
public class ScanningBusImpl extends ScanningEventBus<String, ActorRef, Integer> {
// is needed for determining matching classifiers and storing them in an
// ordered collection
@Override public int compareClassifiers(Integer a, Integer b) {
return a.compareTo(b);
}
// is needed for storing subscribers in an ordered collection
@Override public int compareSubscribers(ActorRef a, ActorRef b) {
return a.compareTo(b);
}
// determines whether a given classifier shall match a given event; it is invoked
// for each subscription for all received events, hence the name of the classifier
@Override public boolean matches(Integer classifier, String event) {
return event.length() <= classifier;
}
// will be invoked for each event for all subscribers which registered themselves
// for the event’s classifier
@Override public void publish(String event, ActorRef subscriber) {
subscriber.tell(event, ActorRef.noSender());
}
}
//#scanning-bus
static
//#actor-bus
public class Notification {
public final ActorRef ref;
public final int id;
public Notification(ActorRef ref, int id) {
this.ref = ref;
this.id = id;
}
}
//#actor-bus
static
//#actor-bus
public class ActorBusImpl extends ActorEventBus<Notification> {
// the ActorSystem will be used for book-keeping operations, such as subscribers terminating
public ActorBusImpl(ActorSystem system) {
super(system);
}
// is used for extracting the classifier from the incoming events
@Override public ActorRef classify(Notification event) {
return event.ref;
}
// determines the initial size of the index data structure
// used internally (i.e. the expected number of different classifiers)
@Override public int mapSize() {
return 128;
}
}
//#actor-bus
@ClassRule
public static AkkaJUnitActorSystemResource actorSystemResource =
new AkkaJUnitActorSystemResource("EventBusDocTest");
private final ActorSystem system = actorSystemResource.getSystem();
@Test
public void demonstrateLookupClassification() {
new JavaTestKit(system) {{
//#lookup-bus-test
LookupBusImpl lookupBus = new LookupBusImpl();
lookupBus.subscribe(getTestActor(), "greetings");
lookupBus.publish(new MsgEnvelope("time", System.currentTimeMillis()));
lookupBus.publish(new MsgEnvelope("greetings", "hello"));
expectMsgEquals("hello");
//#lookup-bus-test
}};
}
@Test
public void demonstrateSubchannelClassification() {
new JavaTestKit(system) {{
//#subchannel-bus-test
SubchannelBusImpl subchannelBus = new SubchannelBusImpl();
subchannelBus.subscribe(getTestActor(), "abc");
subchannelBus.publish(new MsgEnvelope("xyzabc", "x"));
subchannelBus.publish(new MsgEnvelope("bcdef", "b"));
subchannelBus.publish(new MsgEnvelope("abc", "c"));
expectMsgEquals("c");
subchannelBus.publish(new MsgEnvelope("abcdef", "d"));
expectMsgEquals("d");
//#subchannel-bus-test
}};
}
@Test
public void demonstrateScanningClassification() {
new JavaTestKit(system) {{
//#scanning-bus-test
ScanningBusImpl scanningBus = new ScanningBusImpl();
scanningBus.subscribe(getTestActor(), 3);
scanningBus.publish("xyzabc");
scanningBus.publish("ab");
expectMsgEquals("ab");
scanningBus.publish("abc");
expectMsgEquals("abc");
//#scanning-bus-test
}};
}
@Test
public void demonstrateActorClassification() {
//#actor-bus-test
ActorRef observer1 = new JavaTestKit(system).getRef();
ActorRef observer2 = new JavaTestKit(system).getRef();
JavaTestKit probe1 = new JavaTestKit(system);
JavaTestKit probe2 = new JavaTestKit(system);
ActorRef subscriber1 = probe1.getRef();
ActorRef subscriber2 = probe2.getRef();
ActorBusImpl actorBus = new ActorBusImpl(system);
actorBus.subscribe(subscriber1, observer1);
actorBus.subscribe(subscriber2, observer1);
actorBus.subscribe(subscriber2, observer2);
Notification n1 = new Notification(observer1, 100);
actorBus.publish(n1);
probe1.expectMsgEquals(n1);
probe2.expectMsgEquals(n1);
Notification n2 = new Notification(observer2, 101);
actorBus.publish(n2);
probe2.expectMsgEquals(n2);
probe1.expectNoMsg(FiniteDuration.create(500, TimeUnit.MILLISECONDS));
//#actor-bus-test
}
}