State Diagram

 

State diagrams show the dynamic behaviour of a system.  The diagram shows the various states that an object can get into and the transitions that occur between the states.

State:

The state object is a snapshot of an object at a particular point in its life.  A state may have an activity describing the function being performed.

Initial State:

The initial state is the starting state of the object with reference to the behaviour that the diagram explains.  Each state diagram should have only one initial state.

Final State:

Each final state is the ending state of the object with reference to the behaviour that the diagram explains.  There may be multiple final states for an object.

Transition:

The transition link represents the relationship between different states of an object.  The transition guard is a condition which limits the cases in which a transition can occur.  The transition action is performed during the transition and cannot be interrupted.

 

Only one transition can be taken out of a state.  This means that if your diagram shows more than one possible transition from a state, the guards for the transitions must be mutually exclusive.

More State Diagram Concepts:

 

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