package com.hl.account;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * 线程池管理类
 * 
 * @author changcsw 2015-11-6
 * 
 */
public final class ThreadPoolManager {
    // 获取CPU
    private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();

    // 线程池中最少的线程的数量
    private static final int CORE_POOL_SIZE = (CPU_COUNT + 1) > 3 ? (CPU_COUNT + 1) : 3;

    // 线程池中最多的线程的数量
    private static final int MAXIMUM_POOL_SIZE = (CPU_COUNT > 1) ? (CPU_COUNT * 2 + 1) : 5;

    // 空闲线程的最长存活时间
    private static final long KEEP_ALIVE = 1L;

    // 工作队列-阻塞队列
    private static final BlockingQueue<Runnable> WORK_QUEUE = new LinkedBlockingQueue<Runnable>(128);

    // 线程池中线程的创建工厂
    private static final ThreadFactory THREAD_FACTORY = new ThreadFactory() {
        // 原子操作级别的整数，初始值是1
        private final AtomicInteger mCount = new AtomicInteger(1);

        @Override
        public Thread newThread(Runnable r) {
            Thread thread = new Thread(r, "Thread #" + mCount.getAndIncrement()); // 线程名，前缀固定，后缀自增长
            thread.setPriority(Thread.NORM_PRIORITY); // 正常优先级
            return thread;
        }
    };

    /************************************** 线程池中线程的执行的管理器 ******************************************/
    // 普通的任务用这个执行器， 缺点：当没有任务是还会CORE_POOL_SIZE个线程占用资源，优点：无需频繁调度
    public static final ExecutorService EXECUTOR = new ThreadPoolExecutor(CORE_POOL_SIZE, MAXIMUM_POOL_SIZE,
            KEEP_ALIVE, TimeUnit.SECONDS, WORK_QUEUE, THREAD_FACTORY, new ThreadPoolExecutor.DiscardPolicy());
    // 有新的任务就开启新的线程，当没有新任务时会自动回收线程，缺点：频繁调度， 优点：快速处理任务
    public static final ExecutorService CACHED_EXECUTOR = new ThreadPoolExecutor(CORE_POOL_SIZE, Integer.MAX_VALUE,
            60L, TimeUnit.SECONDS, new SynchronousQueue<Runnable>(), THREAD_FACTORY,
            new ThreadPoolExecutor.DiscardOldestPolicy());

    // 当有计划的执行一个任务时用，如检查版本更新,
    public static final ScheduledExecutorService SCHEDULED_EXECUTOR = new ScheduledThreadPoolExecutor(CORE_POOL_SIZE,
            THREAD_FACTORY, new ThreadPoolExecutor.DiscardPolicy());

    /************************************** 线程池中线程的执行的管理器 ******************************************/
}