Abstract: A service-oriented architecture (SOA) is an architectural pattern in computer software design in which application components provide services to other components via a communications protocol, typically over a network. The principles of service-orientation are independent of any vendor, product or technology. A service is a self-contained unit of functionality, such as retrieving an online bank statement. By that definition, a service is an operation that may be discretely invoked. However, in the Web Services Description Language (WSDL), a service is an interface definition that may list several discrete services/operations. And elsewhere, the term service is used for a component that is encapsulated behind an interface. Metrics play an important role in empirical software engineering research as well as in industrial measurement programs. The metrics presented in this paper measure the difference between class inheritance and interface programming. The metric values of class inheritance and interface prove which program is good to use. Our goal is comparing the inheritance and interface concepts in object oriented programming through cohesion- metrics. Complexity, Service granularity metrics
Keywords: SOA, Cohesion, complexity, granulity ,Metrics, WSDL, Inheritance, Services.