1. Real Time Systems Advanced State Machines

2. Behaviour (part 2) - 2 Outline  Simple and Composite States  Transition Segments and Junction Points  Run-to-Completion  Group Transitions and History  Self & Internal Transitions  Exercise

3. Behaviour (part 2) - 3 Simple and Composite States composite simple external view ??

4. Behaviour (part 2) - 4 Simple and Composite States internal view What triggers these transitions?

5. Behaviour (part 2) - 5 Transition Segments transition segments => a transition chain single trigger State?

6. Behaviour (part 2) - 6 Junction Points - 2 types Termination (history) extension

7. Behaviour (part 2) - 7 Design Tip: Unnamed Transitions / Segments Do not leave these “unnamed” transitions in your models!!!

8. Behaviour (part 2) - 8 Run-to Completion  a capsule exhibits run-to-completion semantics:  meaning that a capsule will not be interrupted by the run-time services library while it is executing a run-to-completion step.  when a message is received by a capsule, the entire transition chain executes (before another message is delivered);  data sent with a message is only accessible until the end of the run-to completion  a local copy must be made to preserve the data

9. Behaviour (part 2) - 9 Run-to Completion  consider event “done” while in sub-state “paint”.  what is the sequence of execution code? “Workstation” state“producing” sub-state

10. Behaviour (part 2) - 10 Group Transitions  transitions from hierarchical states that are common to all sub-states  example: “error” while in the sub-state “paint”  what is the sequence of execution code?

11. Behaviour (part 2) - 11 History (*deep)  the deepest sub-state when the containing state was last active.  example: “reset”  what is the sequence of execution code ?

12. Behaviour (part 2) - 12 Self-transition  a transition “out-of” and “back-into” a state  what are the consequences of getting a status message while in the “paint” sub-state?

13. Behaviour (part 2) - 13 Internal-transition  a self-transition which never exits the state  does not fire all entry / exit code up & down the state hierarchy; example: the new “status” transition

14. Behaviour (part 2) - 14 Behaviour Exercise – part 1  Go to the RoseRT on-line Help  Complete the animated Concept Tutorial  entitled: Capsule Hierarchical State Machines  {if you have not already done so}

15. Behaviour (part 2) - 15 Behaviour Exercise – part 2  Refer to the following 2 state diagrams:  Television Satellite Receiver – Top State  Television Satellite Receiver – Operate Sub-state  Assume that initially you are in the Locked sub-state. After that follow the state machine wherever the transition chains take you:  doDiagnostics  followed by changeChannel  followed by orderMovie  followed by status  followed by diag_timeout signal;  assume EvaluateTest = false

16. Behaviour (part 2) - 16 Television Satellite Receiver – Top State changeChannel,

17. Behaviour (part 2) - 17 Television Satellite Receiver – Operate Sub-state