Package-Oriented Software Engineering: A Generic Architecture

N ew methodologies and better techniques are the rule in software engineering, and users of large and complex methodologies benefit greatly from specialized software support tools. However, developing such tools is both difficult and expensive, because developers must implement a lot of functionality in a short time. A promising solution is component-based software development (CBSD), in particular,a CBSD specialization called package-oriented programming (Kevin Sullivan and colleagues, “PackageOriented Programming of Engineering Tools,” Proc. 19th Int’l Conf. Software Eng., IEEE CS Press,Los Alamitos,Calif., 1997.).POP treats regular mass-market applications (such as Microsoft Office or Rational Rose) as large components, taking advantage of the abundant functionality and user familiarity that comes with them. Often, the right tool for a particular job exists as a fullfledged application, but developers or managers do not consider it a component in the traditional sense. POP does away with this restriction. POP fails, however, to satisfy all the requirements of large, complex software engineering tasks. First, it does not support multiuser operation, and fields such as domain analysis and requirements engineering frequently involve more than one user. Second, systems using POP have so far relied only on architecturally compatible components,especially those of Microsoft’s COM specification. POPbased systems like Galileo and the ISI design editor generator use COM because applications that fit their needs implement COM. Integrating with COM applications is attractive, because the communication mechanism is relatively easy to implement and you can achieve a very tight integration. However, such a focus restricts integration to applications primarily compatible with Microsoft Windows; they must also be architecturally compatible with COM. Third, traditional POP also seems to lack platform integration.Today, a typical network is heterogeneous, consisting of a mix of Windows, Linux, and other Unix machines. Each platform provides different tools to accomplish different tasks, and these tools must be integrated in a way that lets them work on the same data remotely. A more generic POP architecture would better serve the development of software engineering environments for large and complex methodologies. Such an architecture emerged from our development experiences with two software engineering research tools: