/* * 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.zeppelin.notebook.repo.zeppelinhub.websocket.scheduler; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; /** * Creates a thread pool that can schedule zeppelinhub commands. * */ public class SchedulerService { private final ScheduledExecutorService pool; private static SchedulerService instance = null; private SchedulerService(int numberOfThread) { pool = Executors.newScheduledThreadPool(numberOfThread); } public static SchedulerService create(int numberOfThread) { if (instance == null) { instance = new SchedulerService(numberOfThread); } return instance; } public static SchedulerService getInstance() { if (instance == null) { instance = new SchedulerService(2); } return instance; } public void add(Runnable service, int firstExecution, int period) { pool.scheduleAtFixedRate(service, firstExecution, period, TimeUnit.SECONDS); } public void addOnce(Runnable service, int firstExecution) { pool.schedule(service, firstExecution, TimeUnit.SECONDS); } public void close() { pool.shutdown(); } }