1. A method performed by a Diameter Routing Agent (DRA) for enabling a user to define message processing rules, the method comprising: receiving, via a user interface of the DRA, a request to define a rule; retrieving metadata associated with a context object; determining that a component specified by the metadata is an enumerated type component; presenting, via the user interface, a first displayed component for the enumerated type component, wherein the first displayed component is associated with a numeric value; presenting, via the user interface, a second displayed component for the enumerated type component, wherein the second displayed component is associated with an alphanumeric value; and receiving, via the user interface, a rule definition, wherein receiving the rule definition comprises receiving a selection of at least one of the first displayed component and the second displayed component.