| /** |
| * 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.hadoop.yarn.service; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.List; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.yarn.YarnException; |
| |
| /** |
| * Composition of services. |
| */ |
| public class CompositeService extends AbstractService { |
| |
| private static final Log LOG = LogFactory.getLog(CompositeService.class); |
| |
| private List<Service> serviceList = new ArrayList<Service>(); |
| |
| public CompositeService(String name) { |
| super(name); |
| } |
| |
| public Collection<Service> getServices() { |
| return Collections.unmodifiableList(serviceList); |
| } |
| |
| protected synchronized void addService(Service service) { |
| serviceList.add(service); |
| } |
| |
| protected synchronized boolean removeService(Service service) { |
| return serviceList.remove(service); |
| } |
| |
| public synchronized void init(Configuration conf) { |
| for (Service service : serviceList) { |
| service.init(conf); |
| } |
| super.init(conf); |
| } |
| |
| public synchronized void start() { |
| int i = 0; |
| try { |
| for (int n = serviceList.size(); i < n; i++) { |
| Service service = serviceList.get(i); |
| service.start(); |
| } |
| super.start(); |
| } catch (Throwable e) { |
| LOG.error("Error starting services " + getName(), e); |
| // Note that the state of the failed service is still INITED and not |
| // STARTED. Even though the last service is not started completely, still |
| // call stop() on all services including failed service to make sure cleanup |
| // happens. |
| stop(i); |
| throw new YarnException("Failed to Start " + getName(), e); |
| } |
| |
| } |
| |
| public synchronized void stop() { |
| if (this.getServiceState() == STATE.STOPPED) { |
| // The base composite-service is already stopped, don't do anything again. |
| return; |
| } |
| if (serviceList.size() > 0) { |
| stop(serviceList.size() - 1); |
| } |
| super.stop(); |
| } |
| |
| private synchronized void stop(int numOfServicesStarted) { |
| // stop in reserve order of start |
| for (int i = numOfServicesStarted; i >= 0; i--) { |
| Service service = serviceList.get(i); |
| try { |
| service.stop(); |
| } catch (Throwable t) { |
| LOG.info("Error stopping " + service.getName(), t); |
| } |
| } |
| } |
| |
| /** |
| * JVM Shutdown hook for CompositeService which will stop the give |
| * CompositeService gracefully in case of JVM shutdown. |
| */ |
| public static class CompositeServiceShutdownHook implements Runnable { |
| |
| private CompositeService compositeService; |
| |
| public CompositeServiceShutdownHook(CompositeService compositeService) { |
| this.compositeService = compositeService; |
| } |
| |
| @Override |
| public void run() { |
| try { |
| // Stop the Composite Service |
| compositeService.stop(); |
| } catch (Throwable t) { |
| LOG.info("Error stopping " + compositeService.getName(), t); |
| } |
| } |
| } |
| |
| } |