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.

Decisions

Figure 8-7. Decisions

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