Design of extensible component-based groupware

Tailoring is identified as a key requirement for CSCW applications. One major tailoring mechanism is the extension of an application at run-time to change its behavior. This article shows how synchronous CSCW component-based applications can be designed to be extensible at run-time. We propose to split the act of tailoring into two steps: the design-time customization of new components in visual builder tools and their insertion into the running application. Thus the customization tool is not required to be part of the application. This article presents a new design pattern for extensibility and gives several examples based on that pattern. With the help of the pattern extensible application frameworks can be systematically created from a non-extensible application design. The di erent possibilities to place insertion points into the application design are discussed with respect to exibility and ease of deployment. Finally, we present the advantages and limitations of this approach.