Support actions with transition via choice/junction pseudostate

[jvalkeal]

This Pseudostate should not have any actions associated with it but it might make sense to have Action with transition leading into and out from the state itself.

[rgreig]

This would be very useful. In many cases in the choice pseudostate, you might have a relatively expensive calculation to perform to determine the target state you want to go into. If you try to do this on guards you end up executing that expensive operation multiple times. If you can execute an action going into the pseudostate, you can make it much more efficient by doing all the logic once and setting a variable or adding a field to the header, and then the guards become trivial.

I have read the UML spec for this (2.5) and I don't believe this goes against anything in the spec.

[jvalkeal]

What I've been thinking is to add actions to source, first, then and last methods.

ChoiceTransitionConfigurer<S, E> source(S source);
ChoiceTransitionConfigurer<S, E> source(S source, Action<S, E> action);
ChoiceTransitionConfigurer<S, E> source(S source, Action<S, E> action, Action<S, E> error);

ChoiceTransitionConfigurer<S, E> first(S target, Guard<S, E> guard);
ChoiceTransitionConfigurer<S, E> first(S target, Guard<S, E> guard, Action<S, E> action);
ChoiceTransitionConfigurer<S, E> first(S target, Guard<S, E> guard, Action<S, E> action, Action<S, E> error);

Then javaconfig would look like:

.withChoice()
	.source(TestStates.S3, sIToChoice())
	.first(TestStates.S30, s30Guard(), choiceToS30())
	.then(TestStates.S31, s31Guard())
	.then(TestStates.S32, s32Guard())
	.last(TestStates.S33, choiceToS33(), choiceToS33Error());

With uml you'd just add behaviours to those incoming/outgoing transitions so it looks a bit simpler to configure. I didn't see no reason why outgoing vertex could not have action as well.

[jvalkeal]

Merged per cec0d24

[gaurav11007]

@jvalkeal :

.withChoice()
.source(TestStates.S3, sIToChoice()) // Here sIToChoice is action for source,right?
.first(TestStates.S30, s30Guard(), choiceToS30())
.then(TestStates.S31, s31Guard())
.then(TestStates.S32, s32Guard())
.last(TestStates.S33, choiceToS33(), choiceToS33Error());

Is this functionality ( Action for Source ) available? If yes then which version? action for guards is available but I am unable to find action for the choice source.