1. Interaction Models

2. Interaction Definition An interaction is a behavior that comprises a set of messages exchanged among a set of objects within a context to accomplish a purpose.

3. Modeling Interactions One of two ways Emphasize its time ordering of messages Emphasize its sequencing of messages in the context of some structural organization of objects.

4. Object Interaction Models The use case and its scenarios serve as a vehicle for organizing the object interactions that take place. Each scenario involves a certain set of interactions. UML uses two different notations and models for object interaction diagrams: one is called sequence diagram and the other a communication diagram. The sequence diagram presents object interaction arranged in time sequence. It shows the object involved in time scenario and the sequence of messages that are exchanged.

5. The communication diagram shows interaction organized around the objects and their messages to each other. These two diagram forms are interchangeable, some CASE tools will automatically generate one from the other. Which one to use is up to the developer. Object Interaction Models

6. Sequence diagram notation Fig 5.9

8. Mapping Scenarios to Sequence Diagrams A user connects to a Customer Manager module named CM. CM makes a self- call to locate the customer. CM then activates a customer object (aCustomer) corresponding to the user. CM redirects the user to aCustomer, at which time the user can update the information associated with aCustomer.