A use-case realization - analysis is a collaboration within the analysis model that describes how a specific use case is realized and performed in terms of analysis classes and interacting analysis objects. It's composed of the following:
- Textual flow-of events description.
- Class diagrams - all the requirements are coordinated onto a class and its objects that the use-case realizations may have.
- Interaction diagrams - Sequence of actions in a use case that begin when an actor invokes the use case by sending some form of message to the system.