The browser sends its request to the top-level controller. This main controller dispatches the input to the appropriate sub-controller. This is why it is necessary to call method DISPATCH_INPUT in the top-level controller.

1. Filling data

For every controller, method DO_HANDLE_DATA is called with a list of form fields that should be handled by this method.
If an error occurs during the data conversion, then this method can also pass one or more messages to the global error object (global_messages).

2. Handle event

Method DO_HANDLE_EVENT is called for exactly one controller. The event is passed on and object htmlb_event is filled if it is an HTMLB-event. Method DO_HANDLE_EVENT has access to object global_messages, in order to determine the additional steps that are necessary, depending on the error. For example, in the case of an error, you can specify that you want to display the data again. You can also set a global_event using method DO_HANDLE_EVENT.

3. Finish input processing