Abstract: A domain\|specific software architecture style is proposed in the paper here. In the architecture style, three software component types are defined: procedure components, object components and agent components. A software bus called TriBus is designed to facilitate interactions among these components and specify one way “citation” relations between different component types and two way “citation” relations between components of the same type. An application example of the software architecture style in the domain of Computer Supported Collaborative Design is given.