controller superclass method invocation in spring 3.0

[Yogesh Mashalkar]

I have a abstract superclass controller as below:

  @Controller
    public abstract class BaseController implements INowExceptionHandler{
    void throwInterceptorExceptionForRedirection(HttpServletRequest request) throws BaseAppException{
		if(request.getAttribute(NOWConstants.EXCEPTION_IN_INTERCEPTOR)!= null && (Boolean)request.getAttribute(NOWConstants.EXCEPTION_IN_INTERCEPTOR)){
			throw new BaseAppException("An exception has occured in one of the Interceptor classes.");
		}
	}
}

There is another controller which extends this class and has a request mapping specified for one of its methods:

@Controller
public class BetaController extends BaseController {
@RequestMapping(value = "/betaCenter")
	public ModelAndView populateBeta(HttpServletRequest request) throws BaseAppException{

//throwInterceptorExceptionForRedirection(request); ***need to replace this explicit invocation call with something like a generic behaviour before the execution of populateBeta() begins***

// some logic stuff which populates content for the view
}
}

Now the issue here is that when dispatcher servlet redirects the request to the specific method (populateBeta in this case), i need to check for some request parameters modified in a separate interceptor class first.
So essentially i have to invoke the throwInterceptorExceptionForRedirection() method before the normal execution of populateBeta() begins.

The reason to eliminate the explicit call in the controller method is because i have multiple controllers & their mapped methods. All controllers extend the BaseController.
It would be great to have throwInterceptorExceptionForRedirection() executed before any URL mapped methods are invoked by the applicationcontext directly.

using point cuts as an option doesnt help as i need the HttpServletRequest object in throwInterceptorExceptionForRedirection().

Any suggestion/help?

[Mudassar Hakim]

Hi, you can try using filter with url pattern "/*" & you still have access to the request object. Let me know if you something better & specific in Spring for the mentioned task.
Apart from this I could really understand why exactly are using InterceptorExceptionForRedirection() ?.
Regards

[Yogesh Mashalkar]

Mudassar,

cannot use filters as i am using the @ExceptionHandler annotation which is applicable only for the specific class(BetaController in this case). this annotation handles all exceptions in all the controllers.
but i am already invoking a interceptor on the "/*" url pattern, which essentially does some loading stuff. if any exception occurs there i am setting a flag in the request object which i can access in the controller.

when the flag is true i am deliberately throwing an exception in the controller, which is handled by the @ExceptionHandler annotation. thats the reason i need to invoke the throwInterceptorExceptionForRedirection() before any other invocations in the controller

i am achieving this but have to add throwInterceptorExceptionForRedirection() call as the first line of all child controllers, since i do not know a way to make spring invoke it automatically for every controller

below is the complete BaseController class:

@Controller
public abstract class BaseController implements INowExceptionHandler{
	
	@Override
	public ModelAndView handleGenericException(HttpServletRequest request, Exception exception) {
		ModelAndView model = new ModelAndView();
		try{
			if(request.getAttribute(NOWConstants.EXCEPTION_IN_INTERCEPTOR)!= null){
				logger.error(exception.getClass().getCanonicalName()+": "+exception.getMessage()+" Redirecting to "+NOWConstants.ERROR_PAGE+".jsp");
			}else{
				logger.error(exception.getClass().getCanonicalName()+" in "+this.getClass().toString()+": Redirecting to "+NOWConstants.ERROR_PAGE+".jsp");
			}
			NowBusinessServiceIfc businessService =	NowBusinessServiceFactory.getBusinessService();
			StaticValueBean staticValueBean = businessService.getStaticTextValue(NOWConstants.ERROR_MESSAGE_KEY_NAME, NOWConstants.ERROR_MESSAGE_KEY_TYPE, TaxonomyUtil.getTaxonomyBean(request));
			model.addObject("errorMessage", staticValueBean.getKeyValue());
			
			model.setViewName(NOWConstants.ERROR_PAGE);
		}catch(Exception e) {
			logger.error(e.getClass().getCanonicalName()+" in "+this.getClass().toString()+": Error getting the messsage to display on "+NOWConstants.ERROR_PAGE+".jsp");
			model.setViewName(NOWConstants.ERROR_PAGE);
		}finally{
			model.setViewName(NOWConstants.ERROR_PAGE);
		}
		return model;
	}
	
	private static Log logger = LogFactoryImpl.getLog(BaseController.class);
	
	void throwInterceptorExceptionForRedirection(HttpServletRequest request) throws BaseAppException{
		if(request.getAttribute(NOWConstants.EXCEPTION_IN_INTERCEPTOR)!= null){
			throw new BaseAppException("An exception has occured in the "+ request.getAttribute(NOWConstants.EXCEPTION_IN_INTERCEPTOR).toString()+" class.");
		}
	}
}

public interface INowExceptionHandler {
	
	@ExceptionHandler(Exception.class)
	public ModelAndView handleGenericException(HttpServletRequest request,Exception exception);
}