并发模型

Master-Worker 模式

Task.class

public class Task {

    private int id;

    private String name;

    private int price;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }
}

Master.class

public class Master {

    // 1. 应该有一个承载任务的集合
    private ConcurrentLinkedQueue<Task> workQueue = new ConcurrentLinkedQueue<>();

    // 2. 使用 HashMap 去承载所有的 worker 对象
    private HashMap<String, Thread> works = new HashMap<>();

    // 3. 使用一个容器承载每一个 worker 并发执行任务的结果集
    private ConcurrentHashMap<String, Object> resultMap = new ConcurrentHashMap<>();

    // 4. 构造方法
    public Master(Worker worker, int workerCount) {
        // 每一个 worker 对象都需要有 Master 的引用，workQueue 用于任务的领取，resultMap 用于任务的提交
        worker.setWorkQueue(this.workQueue);
        worker.setResultMap(this.resultMap);
        for (int i = 0; i < workerCount; i++) {
            // key 表示每一个 worker 的名字，value 表示线程执行对象
            works.put("子节点" + Integer.toString(i), new Thread(worker));
        }
    }

    // 5. 提交方法
    public void submit(Task task) {
        this.workQueue.add(task);
    }

    // 6. 需要有一个执行的方法（启动应用程序 让所有的 worker 工作）
    public void execute() {
        for (Map.Entry<String, Thread> me : works.entrySet()) {
            me.getValue().start();
        }
    }


    // 7. 判断线程是否执行完毕
    public boolean isComplete() {
        for (Map.Entry<String, Thread> me : works.entrySet()) {
            if (me.getValue().getState() != Thread.State.TERMINATED) {
                return false;
            }
        }
        return true;
    }

    // 8. 返回结果集数据
    public Long getResult() {
        Long ret = 0L;
        for (Map.Entry<String, Object> me : resultMap.entrySet()) {
            Integer value = (Integer) me.getValue();
            ret += value;
        }
        return ret;
    }
}

Worker.class

public class Worker implements Runnable {
    private ConcurrentLinkedQueue<Task> workQueue;
    private ConcurrentHashMap<String, Object> resultMap;

    public void setWorkQueue(ConcurrentLinkedQueue<Task> workQueue) {
        this.workQueue = workQueue;
    }

    public void setResultMap(ConcurrentHashMap<String, Object> resultMap) {
        this.resultMap = resultMap;
    }

    @Override
    public void run() {
        while (true) {
            Task input = this.workQueue.poll();
            if (input == null) {
                break;
            }
            // 真正的去做业务处理
            Object output = handle(input);

            this.resultMap.put(Integer.toString(input.getId()), output);
        }
    }

    public Object handle(Task input) {
        return null;
    }

}

MyWorker.class

public class MyWorker extends Worker {

    public Object handle(Task input) {
        Object output = null;
        try {
            // 表示处理 task 任务的耗时，可能是做数据的加工，也可能是操作数据库...
            Thread.sleep(5000);

            output = input.getPrice();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return output;
    }
}

Main.class

public class Main {

    public static void main(String[] args) {
        Master master = new Master(new MyWorker(), Runtime.getRuntime().availableProcessors());
        System.out.println("机器线程数量：" + Runtime.getRuntime().availableProcessors());

        Random random = new Random();
        for (int i = 1; i <= 100; i++) {
            Task task = new Task();
            task.setId(i);
            task.setName("任务" + i);
            task.setPrice(random.nextInt(1000));
            master.submit(task);
        }
        master.execute();

        long start = System.currentTimeMillis();
        while (true) {
            if (master.isComplete()) {
                long end = System.currentTimeMillis() - start;
                Long ret = master.getResult();
                System.out.println("最终结果：" + ret + "，耗时：" + end);
                break;
            }
        }

    }
}

并发模型（一）——Future模式

并发模型（二）——Master-Worker模式