回滚时的java取消ejb计时器

Question

有没有办法确保在发生异常时取消周期性（每10秒一次）和持久性计时器？@Timeout方法的实现如下（从遗留代码简化）：

@Timeout
@TransactionAttribute(REQUIRES_NEW)
public void onTimeout(Timer timer) {
    try {
        doSomeBusinessLogic();
    } catch (Exception e) {
        // throwing this exception makes sure rollback is triggered
        throw new EJBException(e);
    }
}

在doSomeBusinessLogic()中出现任何异常时，需要回滚其事务。这很好用。但是，我还要确保计时器被取消

简单的解决方案是将timer.cancel()放在catch块中。但是，这不起作用，因为取消操作也将回滚（JEE6 Turorial）：

An enterprise bean usually creates a timer within a transaction. If this transaction is rolled back, the timer creation also is rolled back. Similarly, if a bean cancels a timer within a transaction that gets rolled back, the timer cancellation is rolled back. In this case, the timer’s duration is reset as if the cancellation had never occurred.

如果发生异常/回滚，如何确保取消计时器（防止任何进一步的超时）？设置最大重试次数也足够了，但我认为JBoss不支持这一点

应用服务器是JBossAS7.2

Answer 1

我还尝试了Sergey提出的解决方案，似乎效果不错——计时器被取消了。在JBoss EAP 6.2上测试。 以下是我用于测试的代码：

@Stateless
public class TimeoutTest implements TimeoutTestLocal {

@Resource
TimerService timerService;

@Resource
SessionContext sessionContext;

@Timeout
@TransactionAttribute(TransactionAttributeType.NEVER)
public void tmout(javax.ejb.Timer timer) {
    try {
        System.out.println("timout invoked");
        //instead of internal call let's invoke doNothing as
        //this timeout callback is client of TimeoutTest EJB
        //in this way doNothing will be run inside transaction
        TimeoutTestLocal local = sessionContext.getBusinessObject(TimeoutTestLocal.class);
        local.doNothing();  
    } catch (Exception e) {
        timer.cancel();
        System.out.println("Timer cancelled");
    }
}

@Override 
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
public void doNothing() {
    throw new EJBException("RE Exception");
}


@Override
public void schedule() {
    timerService.createTimer(5000, 10000, "test");
}
}

Answer 2

我有一个类似的情况，但是取消catch子句中的计时器似乎有效。我之所以需要它，是为了强制容器（Wildfly）不要重试失败的超时

代码如下所示：

@Timeout
public void onTimeout(Timer timer) {
    try {
        //the other ejb has @TransactionAttribute(TransactionAttributeType.SUPPORTS)
        doSomeBusinessLogicInSomeOtherEjbThatThrowsEjbException();
    } catch (EJBException e) {
        timer.cancel();
        throw e;//this is not necessary since the EJB context has already getRolledBack = true at this point
    }
}

Answer 3

1. 您可以从计时器bean创建新的事务（调用下一个EJB）
2. 您可以更改TA@TransactionAttribute（从不）并从计时器bean创建新的事务（调用下一个EJB）

然后放上计时器。catch块中的cancel（）