| /** |
| * 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. |
| */ |
| package org.apache.activemq.util; |
| |
| import java.util.List; |
| import java.util.concurrent.CopyOnWriteArrayList; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| import org.apache.activemq.Service; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A helper class for working with services together with a useful base class |
| * for service implementations. |
| * |
| * |
| */ |
| public abstract class ServiceSupport implements Service { |
| private static final Logger LOG = LoggerFactory.getLogger(ServiceSupport.class); |
| |
| private AtomicBoolean started = new AtomicBoolean(false); |
| private AtomicBoolean stopping = new AtomicBoolean(false); |
| private AtomicBoolean stopped = new AtomicBoolean(false); |
| private List<ServiceListener>serviceListeners = new CopyOnWriteArrayList<ServiceListener>(); |
| |
| public static void dispose(Service service) { |
| try { |
| service.stop(); |
| } catch (Exception e) { |
| LOG.debug("Could not stop service: " + service + ". Reason: " + e, e); |
| } |
| } |
| |
| public void start() throws Exception { |
| if (started.compareAndSet(false, true)) { |
| boolean success = false; |
| try { |
| doStart(); |
| success = true; |
| } finally { |
| started.set(success); |
| } |
| for(ServiceListener l:this.serviceListeners) { |
| l.started(this); |
| } |
| } |
| } |
| |
| public void stop() throws Exception { |
| if (stopped.compareAndSet(false, true)) { |
| stopping.set(true); |
| ServiceStopper stopper = new ServiceStopper(); |
| try { |
| doStop(stopper); |
| } catch (Exception e) { |
| stopper.onException(this, e); |
| } |
| stopped.set(true); |
| started.set(false); |
| stopping.set(false); |
| for(ServiceListener l:this.serviceListeners) { |
| l.stopped(this); |
| } |
| stopper.throwFirstException(); |
| } |
| } |
| |
| /** |
| * @return true if this service has been started |
| */ |
| public boolean isStarted() { |
| return started.get(); |
| } |
| |
| /** |
| * @return true if this service is in the process of closing |
| */ |
| public boolean isStopping() { |
| return stopping.get(); |
| } |
| |
| /** |
| * @return true if this service is closed |
| */ |
| public boolean isStopped() { |
| return stopped.get(); |
| } |
| |
| public void addServiceListener(ServiceListener l) { |
| this.serviceListeners.add(l); |
| } |
| |
| public void removeServiceListener(ServiceListener l) { |
| this.serviceListeners.remove(l); |
| } |
| |
| protected abstract void doStop(ServiceStopper stopper) throws Exception; |
| |
| protected abstract void doStart() throws Exception; |
| } |