DSSA is based on the concept of an accepted generic software architecture for the target domain. As defined by DSSA, a software architecture describes the topology of software components, specifies the component interfaces, and identifies computational models associated with those components. The architecture must apply to a wide range of systems in the chosen domain; thus it must be general and flexible. It must be established with the consensus of practitioners in the domain.
Once an architecture is established, components that conform to the architecture-i.e., that implement elements of its functionality in conformance with its interfaces-will be acquired. They may be acquired by identifying and modifying (if required) existing components or by specifically creating them. One of the ways they may be created is through automated component generation. DARPA has sponsored work in this area at USC Information Sciences Institute-the AP5 application generator project, and is interested in incorporating this or related technology.
The existence of a domain-specific architecture and conformant component base will dictate a significantly different approach to software application development. The developer will not wait until detailed design or implementation to search for reuse opportunities; instead, he will be driven by the architecture throughout. The architecture and component base will help define requirements and allow construction of rapid prototypes. Design will use the architecture as a starting point. Design and development tools will be automated to "walk through" the architecture and assist the developer in the selection of appropriate components. The ultimate goal is to significantly automate the generation of applications. A major DSSA task is to define such a software lifecycle model and to prototype a supporting toolset.
These activities will be accompanied by extensive interaction with the development community for the target domain, and by technology transition activities. One aspect of this is that each domain team is working closely with a DoD agency that carries out major developments in the designated area. (The GTE team is working with the US Army Communications and Electronics Command.)