After a processor flow has been created with the Processor editor, the flow can be executed at runtime. Technical developers can change the processor runtime behavior according to project requirements.

For example, by default, a UDTT processor does not process errors or exceptions that occur in a state at runtime. If an error occurs in a state when processor is executed, an error page is displayed to the end user. Application developers might want to provide more user-friendly interfaces to the end user, for example, providing an option for the end user to either continue or to cancel a flow. In this case, application developers would have to define error handling states, events and transitions for each processor. If application developers want to implement error handling at runtime for all processors, they can extend the default UDTT processor in runtime.

UDTT processors during runtime are channel specific. The sections describe how to extend a UDTT HTML processor during runtime to demonstrate how to extend UDTT processors. Processors for other channels are extended by using the same method.