| package org.apache.archiva.event; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| import java.util.Collections; |
| import java.util.HashSet; |
| import java.util.Set; |
| import java.util.concurrent.BlockingQueue; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.LinkedBlockingQueue; |
| |
| /** |
| * Simple Async Event Bus implementation |
| * |
| * @author jdumay |
| */ |
| public class AsynchronousEventBus implements EventBus |
| { |
| private final Set<EventObserver> observers = Collections.synchronizedSet(new HashSet()); |
| |
| private final BlockingQueue<Event> events = new LinkedBlockingQueue<Event>(); |
| |
| private final Thread workerThread; |
| |
| private final int threads; |
| |
| public AsynchronousEventBus(int threads) |
| { |
| this.threads = threads; |
| workerThread = new Thread(new WorkerRunnable()); |
| workerThread.start(); |
| } |
| |
| public void emit(EventEmitter emitter, EventMessage message) |
| { |
| events.offer(new Event(emitter, message)); |
| } |
| |
| public void subscribe(EventObserver observer) |
| { |
| observers.add(observer); |
| } |
| |
| public void unsubscribe(EventObserver observer) |
| { |
| observers.remove(observer); |
| } |
| |
| public Set<EventObserver> getObservers() { |
| return new HashSet<EventObserver>(observers); |
| } |
| |
| class WorkerRunnable implements Runnable |
| { |
| private final ExecutorService service; |
| |
| public WorkerRunnable() |
| { |
| service = Executors.newFixedThreadPool(threads); |
| } |
| |
| public void run() |
| { |
| while (true) |
| { |
| dequeueAndExecute(); |
| } |
| } |
| |
| private void dequeueAndExecute() |
| { |
| try |
| { |
| final Event event = events.take(); |
| for (final EventObserver observer : observers) |
| { |
| service.execute(new Runnable() |
| { |
| public void run() |
| { |
| try |
| { |
| observer.observe(event); |
| } |
| finally |
| { |
| //log me |
| } |
| } |
| }); |
| } |
| } |
| catch (InterruptedException e) |
| { |
| //Do nothing |
| } |
| } |
| } |
| } |