android - 协调两个同步适配器的信号量导致 InterruptedException

Question

我有两个同步适配器，我希望每个同步适配器都等到另一个同步适配器完成后再开始执行。我对信号量使用了以下技术:

public class SyncerOne extends AbstractThreadedSyncAdapter {
    protected static Semaphore semaphore = new Semaphore(1);
...
    @Override
    public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult)
    {
            semaphore.acquire();
            doMyStuff();
            semaphore.release();
    }

    public static Semaphore getSemaphore() {
        return semaphore;
    }


public class SyncerTwo extends AbstractThreadedSyncAdapter {
...
    @Override
    public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult)
    {
            Semaphore semaphore = SyncerOne.getSemaphore();
            semaphore.acquire();
            doMyStuff();
            semaphore.release();
    }

当没有人需要等待时一切正常，但是一旦其中一个同步适配器需要在 acquire() 中等待，就会引发 InterruptedException:

10-29 19:08:38.777: W/System.err(419): java.lang.InterruptedException
10-29 19:08:38.787: W/System.err(419):  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1280)

有什么想法吗？

Answer 1

尝试使用 Semaphore.acquireUninterruptibly() 而不是 Semaphore.acquire()。

http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Semaphore.html#acquireUninterruptibly()