From Patterns to Frameworks to Programs

A shortcoming of design patterns is that they are only applicable at the design phase, offering no support during the implementation phase of program development. Part of the problem is that a pattern must be adapted to the problem, a characteristic that cannot be captured by a single reusable implementation. To solve this problem, this paper develops a generative design pattern form called a design pattern template. A pattern template is a pattern form that can be customized using a set of template parameters, to adapt it to the problem. The customized template is used to generate object–oriented framework code, providing implementation support. These pattern templates lead to a process for creating pattern–based programming systems that can be the target of tool support. As an example of such a tool, we present CO2P3S, one implementation of the process. We further argue the need for meta–templates to create extensible tools that allow users to add new pattern templates. To illustrate tool support for meta–templates, we also present MetaCO2P3S. All of the pattern templates in the latest versions of CO2P3S have been created using MetaCO2P3S.