Page 81 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Unit 6: State Modelling

readCard is performed. Note, that transition from Serving Customer state back to the Idle state Notes
could be triggered by cancel event as the customer could cancel transaction at any time.

Figure 6.21: Behavioral State Machine Example - Bank ATM

Source: http://www.uml-diagrams.org/examples/bank-atm-example.html
Serving Customer state is a composite state with sequential substates Customer Authentication,
Selecting Transaction and Transaction. Customer Authentication and Transaction are composite
states by themselves which is shown with hidden decomposition indicator icon. Serving
Customer state has triggerless transition back to the Idle state after transaction is finished. The
state also has exit action ejectCard which releases customer’s card on leaving the state, no matter
what caused the transition out of the state.

Self Assessment

Fill in the blanks:

7. .................. describe all of the possible states of an object as events occur.
8. A ..................pseudo-state is shown with one transition arrives and two or more transitions
leaving.

9. .................. pseudo-states are used to chain together multiple transitions.
10. Entering a .................. pseudo-state indicates that the lifeline of the state machine has
ended.

11. A .................. state is used to remember the previous state of a state machine when it was
interrupted.
12. .................. are used to demonstrate the behavior of an object through many use cases of the
system.

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