content: /**
   * 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.hive.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.hive.conf.HiveConf;
  
  /**
   * CompositeService.
   *
   */
  public class CompositeService extends AbstractService {
  
    private static final Log LOG = LogFactory.getLog(CompositeService.class);
  
    private final 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);
    }
  
    @Override
    public synchronized void init(HiveConf hiveConf) {
      for (Service service : serviceList) {
        service.init(hiveConf);
      }
      super.init(hiveConf);
    }
  
    @Override
    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 ServiceException("Failed to Start " + getName(), e);
      }
  
    }
  
    @Override
    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 given
     * CompositeService gracefully in case of JVM shutdown.
     */
    public static class CompositeServiceShutdownHook implements Runnable {
  
      private final 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);
        }
      }
    }
  
  
  }
  