| /* |
| * 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.datasketches.theta; |
| |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| |
| /** |
| * Pool of threads to serve <i>all</i> propagation tasks in the system. |
| * |
| * @author eshcar |
| */ |
| final class ConcurrentPropagationService { |
| |
| static int NUM_POOL_THREADS = 3; // Default: 3 threads |
| private static volatile ConcurrentPropagationService instance = null; // Singleton |
| private static ExecutorService[] propagationExecutorService = null; |
| |
| |
| private ConcurrentPropagationService() { |
| propagationExecutorService = new ExecutorService[NUM_POOL_THREADS]; |
| } |
| |
| //Factory: Get the singleton |
| private static ConcurrentPropagationService getInstance() { |
| if (instance == null) { |
| synchronized (ConcurrentPropagationService.class) { |
| if (instance == null) { |
| instance = new ConcurrentPropagationService(); |
| } |
| } |
| } |
| return instance; |
| } |
| |
| public static ExecutorService getExecutorService(final long id) { |
| return getInstance().initExecutorService((int) id % NUM_POOL_THREADS); |
| } |
| |
| @SuppressWarnings("static-access") |
| public static ExecutorService resetExecutorService(final long id) { |
| return getInstance().propagationExecutorService[(int) id % NUM_POOL_THREADS] = null; |
| } |
| |
| @SuppressWarnings("static-method") |
| private ExecutorService initExecutorService(final int i) { |
| if (propagationExecutorService[i] == null) { |
| propagationExecutorService[i] = Executors.newSingleThreadExecutor(); |
| } |
| return propagationExecutorService[i]; |
| } |
| } |