/**
 * 隨機(jī)產(chǎn)生ARRAY_LENGTH長(zhǎng)的的隨機(jī)數(shù)組
 */
public class MakeArray {
    // 數(shù)組長(zhǎng)度
    public static final int ARRAY_LENGTH = 4000000;

    public static int[] makeArray() {
        // new一個(gè)隨機(jī)數(shù)發(fā)生器
        Random r = new Random();
        int[] result = new int[ARRAY_LENGTH];
        for (int i = 0; i < ARRAY_LENGTH; i++) {
            // 用隨機(jī)數(shù)填充數(shù)組
            result[i] = r.nextInt(ARRAY_LENGTH * 3);
        }
        return result;
    }
}

public class SumArray {
    private static class SumTask extends RecursiveTask<Integer> {

        // 閾值
        private final static int THRESHOLD = MakeArray.ARRAY_LENGTH / 10;
        private int[] src;
        private int fromIndex;
        private int toIndex;

        public SumTask(int[] src, int fromIndex, int toIndex) {
            this.src = src;
            this.fromIndex = fromIndex;
            this.toIndex = toIndex;
        }

        @Override
        protected Integer compute() {
            // 任務(wù)的大小是否合適
            if ((toIndex - fromIndex) < THRESHOLD) {
                System.out.println(" from index = " + fromIndex + " toIndex=" + toIndex);
                int count = 0;
                for (int i = fromIndex; i <= toIndex; i++) {
                    count = count + src[i];
                }
                return count;
            } else {
                // fromIndex....mid.....toIndex
                int mid = (fromIndex + toIndex) / 2;
                SumTask left = new SumTask(src, fromIndex, mid);
                SumTask right = new SumTask(src, mid + 1, toIndex);
                invokeAll(left, right);
                return left.join() + right.join();
            }
        }
    }

    public static void main(String[] args) {

        int[] src = MakeArray.makeArray();
        // new出池的實(shí)例
        ForkJoinPool pool = new ForkJoinPool();
        // new出Task的實(shí)例
        SumTask innerFind = new SumTask(src, 0, src.length - 1);

        long start = System.currentTimeMillis();

        // invoke阻塞方法
        pool.invoke(innerFind);
        System.out.println("Task is Running.....");

        System.out.println("The count is " + innerFind.join()
                + " spend time:" + (System.currentTimeMillis() - start) + "ms");

    }
}

public class FindDirsFiles extends RecursiveAction {

    private File path;

    public FindDirsFiles(File path) {
        this.path = path;
    }

    @Override
    protected void compute() {
        List<FindDirsFiles> subTasks = new ArrayList<>();

        File[] files = path.listFiles();
        if (files!=null){
            for (File file : files) {
                if (file.isDirectory()) {
                    // 對(duì)每個(gè)子目錄都新建一個(gè)子任務(wù)。
                    subTasks.add(new FindDirsFiles(file));
                } else {
                    // 遇到文件，檢查。
                    if (file.getAbsolutePath().endsWith("txt")){
                        System.out.println("文件:" + file.getAbsolutePath());
                    }
                }
            }
            if (!subTasks.isEmpty()) {
                // 在當(dāng)前的 ForkJoinPool 上調(diào)度所有的子任務(wù)。
                for (FindDirsFiles subTask : invokeAll(subTasks)) {
                    subTask.join();
                }
            }
        }
    }

    public static void main(String [] args){
        try {
            // 用一個(gè) ForkJoinPool 實(shí)例調(diào)度總?cè)蝿?wù)
            ForkJoinPool pool = new ForkJoinPool();
            FindDirsFiles task = new FindDirsFiles(new File("F:/"));

            // 異步提交
            pool.execute(task);

            // 主線程做自己的業(yè)務(wù)工作
            System.out.println("Task is Running......");
            Thread.sleep(1);
            int otherWork = 0;
            for(int i=0;i<100;i++){
                otherWork = otherWork+i;
            }
            System.out.println("Main Thread done sth......,otherWork=" + otherWork);
            System.out.println("Task end");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

public class CountDownLatchTest {
    private static CountDownLatch countDownLatch = new CountDownLatch(2);

    private static class BusinessThread extends Thread {
        @Override
        public void run() {
            try {
                System.out.println("BusinessThread " + Thread.currentThread().getName() + " start....");
                Thread.sleep(3000);
                System.out.println("BusinessThread " + Thread.currentThread().getName() + " end.....");
                // 計(jì)數(shù)器減1
                countDownLatch.countDown();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) throws InterruptedException {
        System.out.println("main start....");
        new BusinessThread().start();
        new BusinessThread().start();
        // 等待countDownLatch計(jì)數(shù)器為零后執(zhí)行后面代碼
        countDownLatch.await();
        System.out.println("main end");
    }

}

public class CyclicBarrierTest {
    private static CyclicBarrier barrier = new CyclicBarrier(4, new CollectThread());

    /**
     * 存放子線程工作結(jié)果的容器
     */
    private static ConcurrentHashMap<String, Long> resultMap = new ConcurrentHashMap<>();

    public static void main(String[] args) {
        for (int i = 0; i < 4; i++) {
            Thread thread = new Thread(new SubThread());
            thread.start();
        }
    }

    /**
     * 匯總的任務(wù)
     */
    private static class CollectThread implements Runnable {

        @Override
        public void run() {
            StringBuilder result = new StringBuilder();
            for (Map.Entry<String, Long> workResult : resultMap.entrySet()) {
                result.append("[" + workResult.getValue() + "]");
            }
            System.out.println(" the result = " + result);
            System.out.println("colletThread end.....");
        }
    }

    /**
     * 相互等待的子線程
     */
    private static class SubThread implements Runnable {

        @Override
        public void run() {
            long id = Thread.currentThread().getId();
            resultMap.put(Thread.currentThread().getId() + "", id);
            try {
                Thread.sleep(1000 + id);
                System.out.println("Thread_" + id + " end1.....");
                barrier.await();
                Thread.sleep(1000 + id);
                System.out.println("Thread_" + id + " end2.....");
                barrier.await();
            } catch (Exception e) {
                e.printStackTrace();
            }

        }
    }
}

/**
 * 數(shù)據(jù)庫(kù)連接
 */
public class SqlConnectImpl implements Connection {

    /**
     * 得到一個(gè)數(shù)據(jù)庫(kù)連接
     */
    public static final Connection fetchConnection(){
        return new SqlConnectImpl();
    }
    
    // 省略其他代碼
}

/**
 * 連接池代碼
 */
public class DBPoolSemaphore {

    private final static int POOL_SIZE = 10;
    // 兩個(gè)指示器，分別表示池子還有可用連接和已用連接
    private final Semaphore useful;
	private final Semaphore useless;
    // 存放數(shù)據(jù)庫(kù)連接的容器
    private static LinkedList<Connection> pool = new LinkedList<Connection>();

    // 初始化池
    static {
        for (int i = 0; i < POOL_SIZE; i++) {
            pool.addLast(SqlConnectImpl.fetchConnection());
        }
    }

    public DBPoolSemaphore() {
        this.useful = new Semaphore(10);
        this.useless = new Semaphore(0);
    }

    /**
     * 歸還連接
     */
    public void returnConnect(Connection connection) throws InterruptedException {
        if (connection != null) {
            System.out.println("當(dāng)前有" + useful.getQueueLength() + "個(gè)線程等待數(shù)據(jù)庫(kù)連接!!"
                    + "可用連接數(shù)：" + useful.availablePermits());
            useless.acquire();
            synchronized (pool) {
                pool.addLast(connection);
            }
            useful.release();
        }
    }

    /**
     * 從池子拿連接
     */
    public Connection takeConnect() throws InterruptedException {
        useful.acquire();
        Connection connection;
        synchronized (pool) {
            connection = pool.removeFirst();
        }
        useless.release();
        return connection;
    }
}

/**
 * 測(cè)試代碼
 */
public class AppTest {

    private static DBPoolSemaphore dbPool = new DBPoolSemaphore();

    private static class BusiThread extends Thread {
        @Override
        public void run() {
            // 讓每個(gè)線程持有連接的時(shí)間不一樣
            Random r = new Random();
            long start = System.currentTimeMillis();
            try {
                Connection connect = dbPool.takeConnect();
                System.out.println("Thread_" + Thread.currentThread().getId()
                        + "_獲取數(shù)據(jù)庫(kù)連接共耗時(shí)【" + (System.currentTimeMillis() - start) + "】ms.");
				//模擬業(yè)務(wù)操作，線程持有連接查詢數(shù)據(jù)
                Thread.sleep(100 + r.nextInt(100));
                System.out.println("查詢數(shù)據(jù)完成，歸還連接！");
                dbPool.returnConnect(connect);
            } catch (InterruptedException e) {
            	e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        for (int i = 0; i < 50; i++) {
            Thread thread = new BusiThread();
            thread.start();
        }
    }
}

public class FutureTaskTest {

    private static class CallableTest implements Callable<Integer> {
        private int sum = 0;

        @Override
        public Integer call() throws Exception {
            System.out.println("Callable 子線程開始計(jì)算！");
            for (int i = 0; i < 5000; i++) {
                if (Thread.currentThread().isInterrupted()) {
                    System.out.println("Callable 子線程計(jì)算任務(wù)中斷！");
                    return null;
                }
                sum = sum + i;
                System.out.println("sum=" + sum);
            }
            System.out.println("Callable 子線程計(jì)算結(jié)束！結(jié)果為: " + sum);
            return sum;
        }
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        CallableTest callableTest = new CallableTest();
        // 包裝
        FutureTask<Integer> futureTask = new FutureTask<>(callableTest);
        new Thread(futureTask).start();

        Random r = new Random();
        if (r.nextInt(100) > 50) {
            // 如果r.nextInt(100) > 50則計(jì)算返回結(jié)果
            System.out.println("sum = " + futureTask.get());
        } else {
            // 如果r.nextInt(100) <= 50則取消計(jì)算
            System.out.println("Cancel...");
            futureTask.cancel(true);
        }
    }
}