Design patterns in object-oriented frameworks

Developing interactive software systems with complex user interfaces has become increasingly common. Given this trend, it is important that new technology be based on flexible architectures that do not require developers to understand all the complexities inherent in a system. Object-oriented frameworks provide an important enabling technology for reusing both the architecture and the functionality of software components. But frameworks typically have a steep learning curve since the user must understand the abstract design of the underlying framework as well as the object collaboration rules or contracts-which are often not apparent in the framework interface-prior to using the framework. In this article, the author describes her experience with developing an object-oriented framework for speech recognition applications that use IBM's ViaVoice speech recognition technology. Design patterns help to effectively communicate the internal framework design and reduce dependence on the documentation.