Android-线程同步

package com.csizg.jniport;


import java.util.ArrayList;
import java.util.List;

/**
 * 与芯片交互线程
 */
public class SpiQueue implements Runnable {

    private static final String TAG = SpiQueue.class.getSimpleName();

    private static final byte INIT = 0;// 初始化
    private static final byte RUNNING = 1;// 执行中
    private static final byte WITING = 2;// 暂停等待中
    private static final byte DONE = 3;// 结束

    private byte state = INIT;// 执行状态

    private static SpiQueue spiQueue = null;

    private SpiQueue() {

    }

    public static SpiQueue getSpiQueue() {
        if (spiQueue == null) {
            spiQueue = new SpiQueue();
        }
        return spiQueue;
    }

    private Thread thread;
    private List<SpiTask> tasks = new ArrayList<>();

    @Override
    public void run() {
        state = RUNNING;
        while (state != DONE) {
            synchronized (this) {
                SpiTask currentTask = getNextTask();
                if (currentTask == null) {
                    System.out.println(TAG + "  run  " + "no task todo begin to waiting");
                    try {
                        state = WITING;
                        wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                } else {
                    try {
                        Thread.sleep(10);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(TAG + "  run  " + "currentTask = " + currentTask.toString());
                }
            }
        }

    }

    private synchronized SpiTask getNextTask() {
        System.out.println(TAG + "  getNextTask  " + "tasks.size() = " + tasks.size());
        if (tasks.size() > 0) {
            SpiTask task = tasks.remove(0);
            return task;
        }
        return null;
    }

    public synchronized void addTask(SpiTask task) {
        System.out.println(TAG + "  addTask  " + "tasks.size() = " + tasks.size() + ", new task : " + task.getCode());
        if (state == DONE) {
            System.out.println(TAG + "  addTask  " + "Thread is DONE : task : " + task.getCode());
            return;
        }
        tasks.add(task);
        if (state != RUNNING) {
            synchronized (this) {
                state = RUNNING;
                System.out.println(TAG + "  addTask notifyAll ");
                notifyAll();
            }
        }
    }

    public synchronized void start() {
        System.out.println(TAG + "   start   " + "state = " + state);
        if (state == RUNNING || state == WITING) {
            return;
        }
        state = INIT;
        // 运行本线程
        tasks.clear();
        if (thread != null) {
            thread.interrupt();
        }
        thread = new Thread(this);
        thread.start();
    }


    public synchronized void stop() {
        state = DONE;
        tasks.clear();
        synchronized (this) {
            notifyAll();
        }
    }
}