Components have been introduced in order to support software reuse. Components are reusable building blocks for larger systems consisting of units (code pieces) and their construction plan. Technologies like COM+, .Net, CORBA JavaBeans and EJBs (or web services which may be considered as web-based components) have been developed to support the component concept. However, components still have the problem of both unavailable and unreliable documentation of their properties. Moreover, a lack of validation support concerning the components' or composed systems' behavior may be observed. In other words, there is a lot of knowledge about how to combine components technically but less experience to validate the interactions between the components.

In this paper we introduce an approach to model components and their compositions as a base for automatic validation techniques to check the components composition and their interactions. The validation aims at deriving the component models from the implementation which allows comparing the specifications with the real components code.