问防止在多线程上下文中使用非线程安全方法

EN

private static final AtomicBoolean used = new AtomicBoolean();

public static void unsafe() throws InterruptedException {
    if(!used.compareAndSet(false, true)) {
        throw new IllegalStateException();
    }
    //do you stuff
    used.set(false);
}

volatile boolean methodBeingUsed = false;
public void doSomething() {
  if (methodBeingUsed) throw new IllegalStateException("You can't do that!");
  try {
    methodBeingUsed = true;
    // do something...
  } finally {
    methodBeingUsed = false;
  }
}

Lock methodLock = new ReentrantLock();
volatile boolean methodBeingUsed = false;
public void doSomething() {
  try {
    lock.lock();
    if (methodBeingUsed) throw new IllegalStateException("You can't do that!");
    methodBeingUsed = true;
  } finally {
    lock.unlock();
  }

  try {
    // do something...
  } finally {
    try {
      lock.lock();
      methodBeingUsed = false;
    } finally {
      lock.unlock();
    }
  }
}