Interceptors and Exceptions

[csanchez]

Hello, I'm using a custom interceptor and I notice when an exception is throwed the postProcess method is not executed. Is this a bug or is the expected way to work?.

I think that postProcess method would be executed beside exceptions. I guess its a common use case set up things in preProcess (maybe a Thread Local) and then clean that things in postProcess and this currently doesn't work when an exception is throwed.

Thanks, Claudio.

[csanchez]

The class MessageInterceptionAdvice has the following code:

        ....
        Message outputMessage = null;
        try {
            outputMessage = (Message) mi.proceed();
        } finally {
            if (outputMessage != null) {
                Stack<MessageInterceptor> postProcessStack = new Stack<MessageInterceptor>();
                postProcessStack.addAll(this.messageInterceptors);
                while (!postProcessStack.empty()) {
                    MessageInterceptor interceptor = postProcessStack.pop();
                    outputMessage = interceptor.postProcess(context, inputMessage, outputMessage);
                }
            }
        }

when mi.proceed() throw an exception outputMessage is always null so the if sentence in the finally is false and thats the reason why the postProcess is not called.

[jeremyg484]

That's a good point, we definitely don't account for teardown of resources in the API, i.e., the equivalent of the afterCompletion callback in HandlerInterceptor. I have added a Jira to consider this for 1.5: https://jira.springsource.org/browse/FLEX-86

In the meantime, you could handle this by having your interceptor also implement ApplicationListener, and listening for the RequestHandledEvent in order to clean up resources.