/** * 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.metrics2.lib; import org.apache.hadoop.metrics2.MetricsExecutor; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.ScheduledThreadPoolExecutor; import java.util.concurrent.ThreadFactory; import java.util.concurrent.atomic.AtomicInteger; /** * Class to handle the ScheduledExecutorService{@link ScheduledExecutorService} used by MetricMutableQuantiles{@link MetricMutableQuantiles} */ public class MetricsExecutorImpl implements MetricsExecutor { @Override public ScheduledExecutorService getExecutor() { return ExecutorSingleton.INSTANCE.scheduler; } @Override public void stop() { if (!getExecutor().isShutdown()) { getExecutor().shutdown(); } } private enum ExecutorSingleton { INSTANCE; private final ScheduledExecutorService scheduler = new ScheduledThreadPoolExecutor(1, new ThreadPoolExecutorThreadFactory("HBase-Metrics2-")); } private static class ThreadPoolExecutorThreadFactory implements ThreadFactory { private final String name; private final AtomicInteger threadNumber = new AtomicInteger(1); private ThreadPoolExecutorThreadFactory(String name) { this.name = name; } @Override public Thread newThread(Runnable runnable) { Thread t = new Thread(runnable, name + threadNumber.getAndIncrement()); t.setDaemon(true); return t; } } }