Dynamic modeling provides a view of a system in which control and sequencing are considered, either within an object (by means of a finite state machine) or between objects (by analysis of object interactions). This chapter addresses dynamic interaction between objects.

Dynamic interaction modeling is based on the realization of the use cases developed during use case modeling. For each use case, it is necessary to determine how the objects that participate in the use case dynamically interact with each other. The object structuring criteria described in Chapter 8 are applied to determine the objects that participate in each use case. This chapter describes how, for each use case, an interaction diagram is developed to depict the objects that participate in the use case and the sequence of messages passed between them. The interaction is depicted on either a communication diagram or a sequence diagram. A narrative description of the object interaction is also provided in a message sequence description. Please note that all references to system in this chapter are to the software system.

This chapter first describes object interaction modeling using communication diagrams and sequence diagrams before describing how they are used in dynamic interaction modeling. It then describes the details of the dynamic interaction modeling approach for determining how objects collaborate with each other. This chapter describes stateless dynamic interaction modeling, also referred to as basic dynamic interaction modeling.