TABLE OF CONTENTS Statemate is a tool that offers a collection of notations for structured analysis. It was developed in the early 1980s by Harel and others out of a need to specify requirements for complex reactive systems. The two basic notations developed for Statemate are statecharts and activity charts. These play the role that Mealy diagrams and DFDs play in Yourdon-style structured analysis, and they can be used instead of Mealy diagrams and DFDs in combination with the other PSA techniques. The distinguishing features of Statemate models and the reason to treat it here are:
The use of statecharts in combination with hierarchical activity charts
The execution semantics of combined statechart-activity chart models
Section 21.1 reviews two of the three notations used by Statemate: activity charts and statecharts. Activity charts are variations of DFDs. The combination of activity charts and statecharts provides a lot of expressive power, in which we can represent activity hierarchy and parallelism in various ways. Section 21.2 discusses the tradeoffs between using activity charts and using statecharts to express activity hierarchy and parallelism. Section 21.3 presents the execution semantics of Statemate.
Statemate uses three notations:
Activity charts. Syntactic variants of DFDs that, just like DFDs, are used to represent an essential decomposition of the SuD.
Statecharts. Used to specify the control activities of the SuD.
Module charts. Used to represent the decomposition of the SuD in computational resources that will run the software.
Here I discuss the use of only activity charts...
