Question

I have got a Spring MDP implemented using Spring DefaultMessageListenderContainer listening to an input queue on WebSphere MQ v7.1. If there is a bad message coming in (that causes RuntimeException), what currently happens is that, the transaction is rolled back, and the message is put back into the queue. However the MDP goes into an infinite loop.

Question 1: For my requirements I would like to be able to shut down the processing the moment it sees a bad message. No retries needed. Is it possible to shutdown the message listener gracefully in case it sees a bad message (as opposed to crude System.exit() or methods of that sort)? I definitely don’t like it to go into an infinite loop.

Edit:

Question 2: Is there a way to stop or suspend the listener container to stop further processing of messages?

Answer 1

I solved the problem in the following manner, not sure if this is the best way, however it works.

1. MDP Implements ApplicationContextAware; I also maintain a listener state (enum with OPEN, CLOSE, ERROR values) MDP Code fragment below:

//context
private ConfigurableApplicationContext applicationContext;

//listener state
private ListenerState listenerState = ListenerState.OPEN;

@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
  this.applicationContext = (ConfigurableApplicationContext) applicationContext;
}
//onMessage method
public void processMessages(....) {
  try {
    process(...);
  } catch (Throwable t) {
    listenerState = ListenerState.ERROR;           
    throw new RuntimeException(...);            
  }    
}

@Override
public void stopContext() {        
  applicationContext.stop();  
}

1. In the java main that loads the spring context i do this:

    //check for errors for exit
    Listener listener = (Listener)context.getBean("listener");
    listenerContainer listenerContainer =
            (ListenerContainer)context.getBean("listenerContainer");

    try {
        while(true) {
            Thread.sleep(1000); //sleep for 1 sec
            if(!listener.getListenerState().equals(ListenerState.OPEN)) {
                listener.stopContext();
                listenerContainer.stop();
                System.exit(1);
            }>             }            
    } catch (InterruptedException e) {
        throw new RuntimeException(e);
    }