不从主线程内执行线程的执行器

Question

public class OrderExecutionThread extends Thread implements Runnable {
    final private static int ORDER_EXEC_THREADS_NUMBER = 10;
    private boolean running = true;
    private boolean flag = true;

    private List<Order> firstSellsList = new ArrayList<>();
    private List<Order> secondSellsList = new ArrayList<>();

    private ManagedDataSource managedDataSource;
    private ExecutorService executorService;

    public OrderExecutionThread(ManagedDataSource managedDataSource) {
        this.managedDataSource = managedDataSource;
        this.executorService = Executors.newFixedThreadPool(ORDER_EXEC_THREADS_NUMBER);
    }

@Override
    public void run() {
        while (running) {
            if (!firstSellsList.isEmpty() && !firstBuysList.isEmpty()) {
                initAndRunExecution(firstBuysList.get(0), firstSellsList.get(0));
        }

    }

    private void initAndRunExecution(Order buy, Order sell) {
        executorService.submit(new OrderExecution(buy, sell, managedDataSource));
    }
}

new Thread(orderExecutionThread).start();

@Override
    public void run() {
        try {
            connection = managedDataSource.getConnection();
            makeExecution(sell, buy);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (!connection.isClosed())
                    connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

    }

我确信这两个列表都不是空的，并且正在调用initandrunexecution，但是没有调用order execution run方法....

Answer 1

我确信这两个列表都不是空的，并且正在调用initAndRunExecution，但是没有调用order execution run方法....

我怀疑这是一个问题，因为FirstSellsList和FirstBuysList不是同步集合。我怀疑其他线程正在添加到这些列表中，但是OrderExecutionThread从来没有看到内存更新，所以只能永远看到空列表。无论何时在线程之间共享数据，都需要担心更新将如何发布，以及线程缓存内存将如何更新。

正如@Fildor在注释中提到的，一个解决方案是使用blockingqueues而不是lists。BlockQueue（例如LinkedBlockingQueue)是一个同步类，因此它负责内存共享。另一个好处是，您不必执行旋转循环来观察条目。

private final BlockingQueue<Order> firstBuys = new LinkedBlockingQueue<>();
private final BlockingQueue<Order> firstSells = new LinkedBlockingQueue<>();

while (!Thread.currentThread().isInterrupted()) {
    // wait until we get a buy
    Order buy = firstBuys.take();
    // wait until we get a sell
    Order sell = firstSells.take();
    initAndRunExecution(buy, sell);
}