Creating transitions between states

In UML modeling, you can add transitions to a state machine diagram to show how an object changes state. A trigger, a guard condition, and an effect are the three optional parts of a transition. Add a trigger to a transition to show that an event must occur for a transition to initiate. Add a guard condition to a transition to show that a particular Boolean condition must be true for a transition to occur. Add an effect to a transition to show that an object performs a particular activity when a guard condition is satisfied.