UML Weekend Crash Course™ - To Parent Directory

SESSION
21
Applying the Basic
Statechart to the Case Study
Session Checklist
✔ Explaining entry and exit actions
✔ Explaining send events
✔ Explaining the order of event execution
✔ Applying the basic Statechart notation to the case study
The Statechart diagram can become very busy. The UML offers two simplifications called
entry and exit actions, along with the ability to send work to other objects. In this session
I show you how to take advantage of these features to simplify your diagram for
the Order object. I also show you how to construct the complete Statechart diagram for the
Order object using the problem statement.
Defining Entry and Exit Actions
Modeling state transitions often results in more than one event that changes the object to
the same state. Each of those events may have a corresponding action. For example, in
Figure 21-1 the Statechart for the Order object says that you can transition the Order from
Tentative to Placed by either receiving the payment for the order or getting an override
authorization. But both events require the same action: issue an order confirmation
(issueConf()).