package com.dwz.concurrency.chapter13; import java.util.ArrayList; import java.util.LinkedList; import java.util.List; /** * 1.任务队列--调度 2.拒绝策略(抛出异常、直接丢弃、阻塞、临时队列)--性能保护 3.init(min) 4.active 5.max * min<=active<=max Quartz/Control-M */ public class SimpleThreadPool { private final int size; private final static int DEFAULT_SIZE = 10; private static volatile int seq = 0; private final static String THREAD_PREFIX = "SIMPLE_THREAD_POOL-"; private final static ThreadGroup GROUP = new ThreadGroup("Pool_Group"); private final static LinkedList<Runnable> TASK_QUEUE = new LinkedList<>(); private final static List<WorkerTask> THREAD_QUEUE = new ArrayList<>(); public SimpleThreadPool() { this(DEFAULT_SIZE); } public SimpleThreadPool(int size) { this.size = size; init(); } private void init() { for (int i = 0; i < this.size; i++) { createWorkTask(); } } public void submit(Runnable runnable) { synchronized (TASK_QUEUE) { TASK_QUEUE.addLast(runnable); TASK_QUEUE.notifyAll(); } } private void createWorkTask() { WorkerTask task = new WorkerTask(GROUP, THREAD_PREFIX + (seq++)); task.start(); THREAD_QUEUE.add(task); } private enum TaskState { FREE, RUNNING, BLOCKED, DEAD } private static class WorkerTask extends Thread { private volatile TaskState taskState = TaskState.FREE; public WorkerTask(ThreadGroup group, String name) { super(group, name); } public TaskState getTaskState() { return this.taskState; } @Override public void run() { OUTER: while (this.taskState != TaskState.DEAD) { Runnable runnable = null; synchronized (TASK_QUEUE) { while (TASK_QUEUE.isEmpty()) { try { this.taskState = TaskState.BLOCKED; TASK_QUEUE.wait(); } catch (InterruptedException e) { e.printStackTrace(); // 线程被打断回到OUTER位置 break OUTER; } } runnable = TASK_QUEUE.removeFirst(); } if (runnable != null) { System.out.println("runnable into..."); this.taskState = TaskState.RUNNING; runnable.run(); this.taskState = TaskState.FREE; } } } public void close() { this.taskState = TaskState.DEAD; } } public static void main(String[] args) { SimpleThreadPool threadPool = new SimpleThreadPool(); // IntStream.range(0, 40).forEach(i -> { // threadPool.submit(() -> { // System.out.println("The runnable " + i + " be serviced by " + Thread.currentThread() + " start."); // try { // Thread.sleep(1000); // } catch (InterruptedException e) { // e.printStackTrace(); // } // System.out.println("The runnable " + i + " be serviced by " + Thread.currentThread() + " finished."); // }); // }); for(int i = 0; i < 40; i++) { threadPool.submit(() -> { System.out.println("The runnable be serviced by " + Thread.currentThread() + " start."); try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("The runnable be serviced by " + Thread.currentThread() + " finished."); }); } } }
该线程池只创建了默认的线程数量,不包含拒绝策略,线程池的打断、销毁和自动扩展线程数量,只保持了线程的最低性能,只是极简版,之后的文章会慢慢扩展
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