This article describes collaborative web based architecture in terms of a collection of generic architectural pattem that define how the different components of the framework work and interact. Based on J2EE specification and on the EJB components, we detailed the implementation of this framework in a distributed web services environment. The main goal of the design and the implementation of the framework was to provide Information System designers with a collaborative web CASE adaptable to their requirements and easy to use and to access. We present the adopted solutions for team collaborative work conflict resolution in a distributed workspace.