com.digitalgeneralists.assurance.model.concurrency.AssuranceThreadPool.java Source code

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Here is the source code for com.digitalgeneralists.assurance.model.concurrency.AssuranceThreadPool.java

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/*
 * Assurance
 * 
 * Created by Mark Johnson
 * 
 * Copyright (c) 2015 Digital Generalists, LLC.
 * 
 */
/*
 * Copyright 2015 Digital Generalists, LLC.
 *
 * Licensed 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 com.digitalgeneralists.assurance.model.concurrency;

import java.util.Collection;
import java.util.LinkedList;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.Phaser;

import org.apache.log4j.Logger;
import org.springframework.stereotype.Component;

@Component("ThreadPool")
public class AssuranceThreadPool implements IAssuranceThreadPool {

    private static final Integer DEFAULT_NUMBER_OF_THREADS = 4;

    private Logger logger = Logger.getLogger(AssuranceThreadPool.class);

    private Collection<Future<?>> futures = new LinkedList<Future<?>>();

    private Phaser lock = new Phaser(0);

    private ExecutorService threadPool = Executors
            .newFixedThreadPool(AssuranceThreadPool.DEFAULT_NUMBER_OF_THREADS);

    public void submit(Runnable task) {
        this.register();
        this.futures.add(threadPool.submit(task));
    }

    public void register() {
        this.lock.register();
    }

    public void unregister() {
        this.lock.arriveAndDeregister();
    }

    public void await() {
        if (lock.getRegisteredParties() > 0) {
            lock.arriveAndAwaitAdvance();
        } else {
            logger.debug("No threads are registered.");
        }
        logger.debug("All threads should be complete.");
    }

    // NOTE: Spring recommends setter-based injection of properties, but this 
    // particular case feels like it could be problematic.
    public void setNumberOfThreads(Integer numberOfThreads) {
        if ((numberOfThreads == null) || (numberOfThreads < 2)) {
            numberOfThreads = AssuranceThreadPool.DEFAULT_NUMBER_OF_THREADS;
        }
        this.threadPool = Executors.newFixedThreadPool(numberOfThreads);
    }
}