CODEWITHSUNDEEP
transitionstatesstate-machine
user716129
user716129

Reputation: 143

Transitioning to previous state

I am designing a state-machine and have one specific state that I can enter from two different states... I am not sure how to go back to the previous state... or am I modeling it wrong ?

to illustrate : 

   | state   | trigger  | nextstate
---------------------------------
1. | initial |   evtX   |    A
2. | initial |   evtY   |    B
3. | B       |   evtX   |    A
4. | A       |   evtZ   | ????

The last row is where I am having trouble. I need to transition to initial state, if A was arrived at from the transiton in row number 1 and I need to transition to state B, if A was arrived at from transition in row number 3.

How can i model this better ?

Upvotes: 0

Views: 201

Answers (1)

ysdx
ysdx

Reputation: 9325

In fact, you have two different A states:

   | state   | trigger  | nextstate
---------------------------------
1. | initial |   evtX   |    A1
2. | initial |   evtY   |    B
3. | B       |   evtX   |    A2
4. | A1      |   evtZ   | initial
4. | A2      |   evtZ   | B

If you want something more powerful, try with Harel/UML statecharts (which have 'superstates, orthogonal regions, and activities as part of a state" [1]). You might have a look at SCXML as weel [2]. I don't know any of them though.

[1] http://en.wikipedia.org/wiki/Harel_statechart#Harel_statechart

[2] http://en.wikipedia.org/wiki/SCXML

Upvotes: 1

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