A Contract-Based Language to Specify Design Components

For component-based software development to be successful in organizations, the software developers must give close attention to the design of components as independent abstractions with well-specified behaviors. Without well-specified behaviors the possibility to distribute and acquire software components will be limited. In this article, we present a contract-based approach to analyze and model the properties of design components and their composition in order to detect and correct composition errors. This approach permits to characterize the structural, interface and behavioural aspects of design component. As a matter of fact, we give a specific form of their instantiation, evolution and integration. To enable this, we present a pattern contract language that captures the structural and behavioral requirements associated with a range of patterns, as well as the system properties that are guaranteed as a result. In addition, we propose the use of the LOTOS language as an ADL for formalizing these aspects. We illustrate the approach by applying it to a standard design pattern.