VALIDATING DATA WITHIN CONTAINER OBJECTS HANDLED BY VIEW CONTROLLERS

A method and apparatus in a data processing system for performing validation of user input. User input is received in a container displayed in a graphical user interface, wherein presentation of the container and the user input to the container are handled by a view controller. Responsive to receiving the user input, a call is sent to a validation object by the view controller. Responsive to the call, the validation object tests the user input using a criteria, wherein the rule is separate from the view controller.