1. The design, implementation, integration and evaluation of a Statechart service.
By Xin Bai
Feb 7, 2002

2. Why use statecharts?
Statechart extends the classical state transition diagram.
It saves the number of the state and arrow in the diagram.
Most importantly it supports concurrency.

3. Backgrounds:
David Harel invented this language in 1983.
The STATEMATE system by I-Logix Israel., Ltd. has implemented statechart language.

4. Statecharts extend classical state transition diagrams
Depth, hierarchy or modularity support No
Yes
Number of transition arrows
Uneconomical
Economical
Number of states
Grow exponentially
Concurrency Support
No (sequential in nature)

5. From state transition diagrams to statechartsB D e f h
g[c] A C B
g[c] e f h
States: A, B, C, D
Events: e, f, g
Condition: c
D = A XOR C
g[c] triggers the transition from A to C if and when g occurs, but only if c is true at that time

6. History entrance to a state overrides the default arrowB H f C D

7. AND decomposition, actions and chain reactionB C A
f/g E G F I J
m/e
n/f H D e k n g

8. Objectives:
Design a textual expression for a simplified statechart just like blueprint.
Implement a statechart service so that users can use this textual expression to develop concurrent application.
Implement a sample application

9. Literature:
D. Harel, Statecharts: A Visual Formalism for Complex Systems, Science of Computer Programming 8 (1987), pp
D. Harel, A. Pnueli, J.P. Schmidt, and R. Sherman, On the Formal Semantics of Statecharts, in Proc. 2nd Symp. on Logic in Computer Science (LICS 87), pages IEEE Computer Society Press, 1987

10. Thank you!