State chart diagram and multiple actions

Question

Can a transition have two or more actions?

For example:

       event[condition]/action1;action2
stateA -------------------------------------------> stateB

Can you clarify which notation scheme you're using? – Lightness Races in Orbit Jan 31 '13 at 13:46 — Lightness Races in Orbit, Jan 31 '13 at 13:46
standar UML state chart diagram. – user1993478 Jan 31 '13 at 13:48 — user1993478, Jan 31 '13 at 13:48

score 1 · Answer 1 · answered Jan 31 '13 at 13:55

Yes.

From Wikipedia:

In UML, a state transition can directly connect any two states. These two states, which may be composite, are designated as the main source and the main target of a transition. Figure 7 shows a simple transition example and explains the state roles in that transition. The UML specification prescribes that taking a state transition involves executing the following actions in the following sequence (see Section 15.3.14 in OMG Unified Modeling Language (OMG UML), Infrastructure Version 2.2):

Evaluate the guard condition associated with the transition and perform the following steps only if the guard evaluates to TRUE.

Exit the source state configuration.

Execute the actions associated with the transition.

Enter the target state configuration.

I have been unable to find succint wording to define this in the UML specification, but diagrams and further wording on the Wikipedia article (which is well-referenced) seem to imply that you should use ; as a separator, as in your example.

However, intuitively I would expect a system's state to change after each action has been taken, so (again intuitively) I would recommend minimizing your use of multiple actions per transition. Instead consider adding intermediate states.

my doubt was the fact that the action is atomic :) thanks anyway — user1993478, Jan 31 '13 at 13:59

State chart diagram and multiple actions

1 Answers1