Client-Level Exception Handlers

Support
#1

Hello,

I struggle to display a notification from middleware service to client tier.
I made a new Exception class that actually is triggered in Catalina.out and I made a ControlledExceptionHandler too.
I put the ControlledExceptionHandler under Screens package (I’m not sure that is correct, I tried to put in Core level but I don’t have access to AbstractUiExceptionHandler base class).
Unfortunatelly I don’t know how to trigger (access) this handler in Middlleware service.
(I can only injected in client tier level).

Middleware Service

try{

}catch(Exception e){
throw new ControlledException("text"); //it works
//handler call??
}

ControlledExceptionHandler

@Component("myapp_ControlledExceptionHandler")
 public  class ControlledExceptionHandler extends AbstractUiExceptionHandler {

        	public ControlledExceptionHandler() {
 		super(ControlledException.class.getName());

 	}

        	 @Override
 	 protected void doHandle(String className, String message, @Nullable Throwable throwable, UiContext context) {
//	     windowManager.showNotification("Title", message, Frame.NotificationType.ERROR);
                 context.getNotifications().create(Notifications.NotificationType.ERROR)
                         .withCaption("`My message which has to be displayed in client tier` ")
                         .withDescription(message)
                         .show();


 	 }

    @Override
    public boolean handle(Throwable exception, UiContext context) {
        return super.handle(exception, context);
    }

    @Override
    protected boolean canHandle(String className, String message, @Nullable Throwable throwable) {
        return StringUtils.containsIgnoreCase(message, " ");
    }

Please advise!

#3

Hello @neutrino,

In Middleware Service you are throwing a ControlledException with the “text” message.

In ControlledExceptionHandler you are trying to handle an exception with a message that contains a space. But there is no space in the error message (“text”).
The canHandle(String className, String message, @Nullable Throwable throwable) method is used if the name of the exception class is insufficient to make a decision whether this handler can be applied to the exception.

Regards,
Gleb

#5

Hello Gleb,

Now it works but doesn’t help me too much.
It worksonly if in the client method I don’t cath the ControlledException. When the ControlledException arrise the handler do its job.

But I can throws Exception at the method signature level and cath the ControlledException below (without use any handler).

catch (ControlledException d){
  notifications.create()
                    .withCaption("My message which has to be displayed in client tier" )
                    .show();

        }

If I use general Exception the handler doesn’t work.
I need to catch all exceptions without Controlled exception(with a notification) and Controlled exception(with another/different notification). Of course I can do treating all exceptions but I thouhgt the handler can help me.

catch (Exception e) {
//my code
//my notification
}

Regards,
-n

#7

Hello @neutrino,

Link to documentation.

Unhandled exceptions thrown on the client tier or passed from Middleware, are passed to the special handlers mechanism of the Web Client block.

Client-level exception handlers handle only unhandled exceptions thrown on the client tier or passed from Middleware. Therefore, you cannot handle exceptions with client-level exception handlers that you already handle in Middleware service.

Regards,
Gleb

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