Chapter 17 Component-based software engineering. The objective of this chapter is to describe an approach to software reuse based on the composition of reusable, standardized components. When you have read this chapter you will: know that component-based software engineering is concerned with developing standardized components based on a component model, and composing these into application systems; understand what is meant by a component and a component model. | Chapter 17 Component-based software engineering Lecture 1 1 Chapter 17 Software reuse Topics covered Components and component models CBSE processes Component composition 2 Chapter 17 Software reuse Component-based development Component-based software engineering (CBSE) is an approach to software development that relies on the reuse of entities called ‘software components’. It emerged from the failure of object-oriented development to support effective reuse. Single object classes are too detailed and specific. Components are more abstract than object classes and can be considered to be stand-alone service providers. They can exist as stand-alone entities. 3 Chapter 17 Software reuse CBSE essentials Independent components specified by their interfaces. Component standards to facilitate component integration. Middleware that provides support for component inter-operability. A development process that is geared to reuse. 4 Chapter 17 Software reuse CBSE and design principles Apart from . | Chapter 17 Component-based software engineering Lecture 1 1 Chapter 17 Software reuse Topics covered Components and component models CBSE processes Component composition 2 Chapter 17 Software reuse Component-based development Component-based software engineering (CBSE) is an approach to software development that relies on the reuse of entities called ‘software components’. It emerged from the failure of object-oriented development to support effective reuse. Single object classes are too detailed and specific. Components are more abstract than object classes and can be considered to be stand-alone service providers. They can exist as stand-alone entities. 3 Chapter 17 Software reuse CBSE essentials Independent components specified by their interfaces. Component standards to facilitate component integration. Middleware that provides support for component inter-operability. A development process that is geared to reuse. 4 Chapter 17 Software reuse CBSE and design principles Apart from the benefits of reuse, CBSE is based on sound software engineering design principles: Components are independent so do not interfere with each other; Component implementations are hidden; Communication is through well-defined interfaces; Component platforms are shared and reduce development costs. 5 Chapter 17 Software reuse Component standards Standards need to be established so that components can communicate with each other and inter-operate. Unfortunately, several competing component standards were established: Sun’s Enterprise Java Beans Microsoft’s COM and .NET CORBA’s CCM In practice, these multiple standards have hindered the uptake of CBSE. It is impossible for components developed using different approaches to work together. 6 Chapter 17 Software reuse CBSE problems Component trustworthiness - how can a component with no available source code be trusted? Component certification - who will certify the quality of components? Emergent property prediction - how can the emergent .
