MagicDraw 18.5 Documentation

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A transition is a directed relationship between a source vertex and a target vertex. It can be a part of a compound transition, which takes the state machine from one state configuration to another, representing the complete response of the state machine to an occurrence of an event of a particular type. The transition relationship is created between two states. The transition specifies event occurrences and guard conditions.

When these events occur and conditions are satisfied with the object in the source, state will perform the specified effect and will enter the target state. So, in the transition, the main subjects are as follows:

  • Event trigger and its parameter
  • Guard condition
  • Effect

On a transition path the event trigger, guard condition, and effect has the following syntax:
< event name> (< parameter >) [<guard condition >] / <effect name>

An example of the transition.

 

In the preceding example, the transition relationship is created from the Ringing state to the Connected state. The transition has the specified event - phone answered, and the specified effect - enable speech. When the phone answered event occurs, the Ringing state performs the speech effect, and then the Connected state is
entered.

The event on the transition is specified as event of the concrete type. The event trigger is the event whose reception in the source state makes the transition eligible to fire. That is, the trigger is specified by the event. Event types are as follows:

  • Any Receive Event
  • Call Event
  • Change Event
  • Signal Event
  • Time Event

• You can assign an event type in the Transition Specification window, or there is a quick way to assign an event type straight on the transition from the diagram pane.
• The effect on the transition is specified as one of the behaviors types.
• You can format the transition symbol properties in the Symbol Properties dialog.

You can specify transition properties in the Transition Specification window. In the same window, you can find the description of each property. Descriptions are presented in the description area of the Specification window.

 

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