Substates and Superstates (Statechart Module)

You can use regions to place states within states. In this situation, the state that contains the region is called a superstate. The states inside the region are called substates. For example, the following figure shows a superstate and substates.

In the previous figure, the Initial pseudostate specifies that the statechart enters State 2 immediately after entering State 1.

Note  While the statechart is in a substate, the statechart can take any transition, or execute any static reaction, associated with the enclosing superstate. Transitions and static reactions of the superstate have higher priority than transitions and static reactions of a substate.

You can bypass this initial state by creating transitions to and from substates directly. The following figure shows this situation:

In the previous figure, the statechart follows the same initial behavior, which means that the statechart enters State 2 first. However, State 2 now has a transition (1) to State 4. Similarly, State 3 has a transition (2) to State 6. If the statechart takes transition 1 and enters State 4, the Initial pseudostate in Region 2 specifies that the statechart enters State 5. However, if the statechart takes transition 2, the statechart bypasses State 5 and enters State 6.

Note  You can place regions inside substates and substates inside these regions. In this situation, a substate becomes a superstate.