SimpleThreadPool minimalist version

Package Penalty for com.dwz.concurrency.chapter13; 

Import java.util.ArrayList;
 Import java.util.LinkedList;
 Import java.util.List; 

/ ** 
 * 1. Task Queue - Scheduling 2. deny policy (an exception is thrown, discarded directly, blocking, temporary queue) - protection performance 3.init (min) 4.active 5.max 
 * min <= Active <= max the Quartz / Control-M 
 * / 
public  class SimpleThreadPool {
     Private  Final  int size;
     Private  Final  static  int of 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.");
            });
        }
    }
}