We use the term AdviceObject to refer to an object that contains advice. In AspectCocoa our advice objects will generally respond to some variation of before: or after: . before: and after: will get called on all AdviceObjects that have been assigned to a given PointCut and whenever a JoinPoint within the scope of that PointCut is encountered during the execution of a program. In general, AdviceObjects are applied to PointCuts via the creation of Aspects. The functionality of before: and after: will vary depending on what purpose the Aspect was created for. But a most simplistic example is the ACLoggingAdvice class.
see AdviceObject for specific usage.