Introduction
A system sequence diagram (SSD) is a fast and easily created artifact that illustrates input and output events related to the systems under discussion. They are input to operation contracts andmost importantlyobject design.The UML contains notation in the form of sequence diagrams to illustrate events from external actors to a system.[View full size image]UP artifact influence emphasizing system sequence diagrams is shown in Figure 10.1. The use case text and its implied system events are input to SSD creation. The SSD operations (such as enterItem ) can in turn be analyzed in the operation contracts, detailed in the Glossary, andmost importantserve as the starting point for designing collaborating objects.