Akka/Scala example source code file (ConsistentHashingRouterDocTest.java)

This example Akka source code file (ConsistentHashingRouterDocTest.java) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

actor, akka, consistenthashmapper, entry, evict, get, hello, hi, not_found, object, route, serializable, string, test, testing, testkit

The ConsistentHashingRouterDocTest.java Akka example source code

/**
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 */
package docs.jrouting;

import akka.testkit.AkkaJUnitActorSystemResource;

import org.junit.ClassRule;
import org.junit.Test;

import akka.testkit.JavaTestKit;
import akka.actor.ActorSystem;

//#imports1
import akka.actor.UntypedActor;
import akka.routing.ConsistentHashingRouter.ConsistentHashable;

import java.util.Map;
import java.util.HashMap;
import java.io.Serializable;
//#imports1


//#imports2
import akka.actor.Props;
import akka.actor.ActorRef;
import akka.routing.ConsistentHashingPool;
import akka.routing.ConsistentHashingRouter;
import akka.routing.ConsistentHashingRouter.ConsistentHashMapper;
import akka.routing.ConsistentHashingRouter.ConsistentHashableEnvelope;
//#imports2

public class ConsistentHashingRouterDocTest {

  @ClassRule
  public static AkkaJUnitActorSystemResource actorSystemResource =
    new AkkaJUnitActorSystemResource("ConsistentHashingRouterDocTest");

  private final ActorSystem system = actorSystemResource.getSystem();

  static
  //#cache-actor
  public class Cache extends UntypedActor {
    Map<String, String> cache = new HashMap<String, String>();

    public void onReceive(Object msg) {
      if (msg instanceof Entry) {
        Entry entry = (Entry) msg;
        cache.put(entry.key, entry.value);
      } else if (msg instanceof Get) {
        Get get = (Get) msg;
        Object value = cache.get(get.key);
        getSender().tell(value == null ? NOT_FOUND : value, 
          getContext().self());
      } else if (msg instanceof Evict) {
        Evict evict = (Evict) msg;
        cache.remove(evict.key);
      } else {
        unhandled(msg);
      }
    }
  }

  //#cache-actor
  static
  //#cache-actor
  public final class Evict implements Serializable {
    private static final long serialVersionUID = 1L;
    public final String key;
    public Evict(String key) {
      this.key = key;
    }
  }

  //#cache-actor
  static
  //#cache-actor
  public final class Get implements Serializable, ConsistentHashable {
    private static final long serialVersionUID = 1L;
    public final String key;
    public Get(String key) {
      this.key = key;
    }
    public Object consistentHashKey() {
      return key;
    } 
  }

  //#cache-actor
  static
  //#cache-actor
  public final class Entry implements Serializable {
    private static final long serialVersionUID = 1L;
    public final String key;
    public final String value;
    public Entry(String key, String value) {
      this.key = key;
      this.value = value;
    }
  }

  //#cache-actor
  static
  //#cache-actor
  public final String NOT_FOUND = "NOT_FOUND";
  //#cache-actor  


  @Test
  public void demonstrateUsageOfConsistentHashableRouter() {

    new JavaTestKit(system) {{

      //#consistent-hashing-router      
      
      final ConsistentHashMapper hashMapper = new ConsistentHashMapper() {
        @Override
        public Object hashKey(Object message) {
          if (message instanceof Evict) {
            return ((Evict) message).key;
          } else {
            return null;
          }
        }
      };

      ActorRef cache = system.actorOf(
          new ConsistentHashingPool(10).withHashMapper(hashMapper).props(
              Props.create(Cache.class)), 
        "cache");

      cache.tell(new ConsistentHashableEnvelope(
        new Entry("hello", "HELLO"), "hello"), getRef());
      cache.tell(new ConsistentHashableEnvelope(
        new Entry("hi", "HI"), "hi"), getRef());

      cache.tell(new Get("hello"), getRef());
      expectMsgEquals("HELLO");

      cache.tell(new Get("hi"), getRef());
      expectMsgEquals("HI");

      cache.tell(new Evict("hi"), getRef());
      cache.tell(new Get("hi"), getRef());
      expectMsgEquals(NOT_FOUND);

      //#consistent-hashing-router
    }};
  }

}