8.4 Decisions
A decision involves selecting one
control-flow
transition out of many control-flow transitions based upon a
condition. For example, once a report is printed by the project
management system, other reports may be selected and printed if the
project manager chooses to print more reports.
In the UML, a decision is shown as a diamond shape with incoming
control-flow transitions and outgoing control-flow transitions where
each outgoing control-flow transition is labeled with a guard
condition in square brackets indicating the condition that must be
satisfied for the transition to fire, or occur. Figure 8-7 shows that once a report is printed, a project
manager may choose to print more reports. Notice that because the
diamond shape is in the project manager's swimlane,
the project manager is responsible for making the decision.
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