Java 8 - 可重入锁/锁定对象

Question

我想知道使用 ReentrantLock 是否可以解决我的问题；我试图“锁定”（防止其他线程访问/使用它）一个对象，直到某个操作完成，然后解锁它以便其他线程可以访问它。我想过使用 sun 的 Unsafe#monitorEnter/exit 但这可能会导致死锁。

想象以下情况：

public void doSomething() {
    Object object = someObject;

    // Object should be locked until operation is complete.
    doSomethingElse(object);

    // Object should now be unlocked so other threads can use/access it.
}

public void doSomethingElse(Object object) {
    // Something happens to the object here
}

这会是解决方案吗？

  ReentrantLock reentrantLock = new ReentrantLock();

  public void doSomething() {
        Object object = someObject;

        // Object should be locked until operation is complete.
        reentrantLock.lock();
        doSomethingElse(object);

        reentrantLock.unlock();

        // Unlock object for other threads after complete.
    }

    public void doSomethingElse(Object object) {
        // Something happens to the object here
    }

提前致谢。

Answer 1

我建议在 doSomethingElse 上使用同步方法

public void doSomething() {
    Object object = someObject;

    // Object should be locked until operation is complete.
    doSomethingElse(object);
    // Unlock object for other threads after complete.
}

public synchronized void doSomethingElse(Object object) {
    // Something happens to the object here
}