001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.metrics2.lib;
020
021import java.util.concurrent.ScheduledExecutorService;
022import java.util.concurrent.ScheduledThreadPoolExecutor;
023import java.util.concurrent.ThreadFactory;
024import java.util.concurrent.atomic.AtomicInteger;
025
026import org.apache.hadoop.metrics2.MetricsExecutor;
027import org.apache.yetus.audience.InterfaceAudience;
028
029/**
030 *  Class to handle the ScheduledExecutorService{@link ScheduledExecutorService} used by
031 *  MetricsRegionAggregateSourceImpl, and
032 *  JmxCacheBuster
033 */
034@InterfaceAudience.Private
035public class MetricsExecutorImpl implements MetricsExecutor {
036
037  @Override
038  public ScheduledExecutorService getExecutor() {
039    return ExecutorSingleton.INSTANCE.scheduler;
040  }
041
042  @Override
043  public void stop() {
044    if (!getExecutor().isShutdown()) {
045      getExecutor().shutdown();
046    }
047  }
048
049  private enum ExecutorSingleton {
050    INSTANCE;
051    private final transient ScheduledExecutorService scheduler = new ScheduledThreadPoolExecutor(1,
052        new ThreadPoolExecutorThreadFactory("HBase-Metrics2-"));
053  }
054
055  private final static class ThreadPoolExecutorThreadFactory implements ThreadFactory {
056    private final String name;
057    private final AtomicInteger threadNumber = new AtomicInteger(1);
058
059    private ThreadPoolExecutorThreadFactory(String name) {
060      this.name = name;
061    }
062
063    @Override
064    public Thread newThread(Runnable runnable) {
065      Thread t = new Thread(runnable, name + threadNumber.getAndIncrement());
066      t.setDaemon(true);
067      return t;
068    }
069  }
070}