UML Weekend Crash Course™ - To Parent Directory

218
Sunday Morning
receive pmt / issueConf()
Order is filled /
issueCustomerStmt()
Filled
Tentative
Placed
authorize override / issueConf()
cancel /
issueCustomerStmt()
Cancelled
Figure 21-1 Redundant actions entering and exiting the Placed state of the Order
In Session 20, you discovered that the state icon could be expanded to reveal the internal
transitions compartment. In that compartment you can model something called entry
actions. Entry actions provide a means to eliminate the redundancy in Figure 21-1.
Whenever you discover an action that must take place with every event that transitions
to the same state, you can write the action(s) once as an entry action. Figure 21-2 shows
the entry action notation, entry/action(s). When the redundant action is replaced by the
entry action, you can remove it from the individual event arrows. This simplifies the diagram
while preserving the same meaning. You would read the diagram to say, “Every time
you enter this state issue an order confirmation.”
receive pmt
Tentative
Placed
entry/issueConf()
Order is filled /
issueCustomerStmt()
Filled
Figure 21-2
authorize override
Consolidating the entry actions
cancel /
issueCustomerStmt()
Cancelled