Hagi Lachover

Digital Library

ACM Software System Award

Israel - 2007



For Statemate, the first embodiment in a commercial computer-aided software engineering tool of a rigorous approach to model-driven development based on statecharts, and employing techniques for the executability of visual formalisms, and for code-generation.

Statemate was designed and built between 1984 and 1986 by a team composed of David Harel, Hagi Lachover, Amnon Naamad, Amir Pnueli, Michal Politi, Rivi Sherman, Mark Trakhtenbrot, and Aron Trauring at Ad Cad, Ltd., which later became the R&D division of I-Logix, Inc. It has been available continuously since then in several increasingly sophisticated versions.

Statemate had a fundamental impact on software and systems engineering. The ideas first appearing in Statemate underlie today's most powerful and most widely used tools in software and systems engineering. Before Statemate, graphical design notations supported by CASE (computer-aided software engineering) tools did not have formal foundations, could not execute models, and could not generate code that ran. They were like programming language environments without compilers and interpreters.

In 1983, David Harel developed statecharts, a graphical language for finite-state machines. The language provided natural and easy-to-grasp abstraction features, such as hierarchy, parallelism, and aggregation, which facilitate human understanding of complex system behavior. Harel and Pnueli then identified the class of reactive systems, for which such behavioral aspects were most problematic. Reactive systems include concurrent and real-time systems, embedded systems, and interactive systems. Statecharts proved to be the right notation to model them.

In early 1984, Harel, Lachover, and Pnueli, together with Ido Lachover, co-founded Ad Cad, Ltd., to build a CASE tool supporting statecharts. One of the group's first tasks was to figure out how to embed statecharts into a broader framework that would capture the structure and functionality of a large complex system. They devised two more diagrammatic languages: activity charts, to specify functionality, and module charts, to specify structure.

The first version of Statemate was operational in 1986. A Statemate user could draw a model's artifacts, check and analyze them, produce documentation, and manage their configurations and versions. Most importantly, Statemate could execute the model's functional and behavioral descriptions and could automatically generate executable code.

Statemate was the first real-world tool for model-driven system development (MDD). In the 1990s, statecharts were incorporated into the Unified Modeling Language (UML), the industry-standard language for specifying, visualizing, constructing, and documenting the artifacts of software systems, and the basis for many recent CASE tools.