Component Based Software Engineering (CBSE) Chris Sholar 11-03-03 CS5667

CBSE Emphasis Design and construction of computer-based systems using reusable software “components”. Goal is to create a catalog of software components that would be appropriate to use in given system requirements. Leads to some questions…

Possible to construct complex systems using a catalog of reusable software components? Can this be accomplished in a timely cost-efficient manner? Can the programmers be convinced to use this method of reuse, rather than reinvent? (XP programming style?) Can the catalog of components be made available to whoever needs it?

Why Is It Used? The stereo example Motivation Components rather than discrete parts. Simpler to implement once created, cataloged Leads to more consistent product design and implementation…MS office suite.

The Process Who does it? Why important? Steps? Software engineers Previous statements Steps? Parallel activities Domain engineering Component based engineering

Work product Is it right? Operational software created from existing and newly developed software components Is it right? Uses same SQA practices applied to any SE process Formal reviews Specialized reviews to cover acquired components. Testing, testing, testing.

Engineering CB Systems Establish requirements the old fashioned way. Architectural design is created Differs from standard because team then examines requirements for possible component use. Asks these questions: COTS components available? Internally developed reusable components available? Are the interfaces from components compatible with architecture of the system?

Goal: Design team attempts to modify or remove system requirements that cannot be implemented with COTS or internally created components. If this cannot be done, the traditional method is then applied. Can be to create reusable components, or create proprietary software.

When Available Components Work New SE activities Component qualification Component adaptation Component composition Component update

Component qualification Do the services provided by the component meet the needs of the system? Component adaptation Can the component be modified to meet the needs of the system? Component composition The system architecture dictates the composition of the component. Component update When COTS are used, update becomes difficult because of third-party constraints.

The CBSE Process Model Adds Incorporation into typical evolutionary process model. Adds Qualifications for interface Adaptation of components Assembles components Updates components

Process Model Parallel tracks Domain engineering Component based development Establishes set of software components that can be reused by the software engineer The major part of the work

Homework Identify the parts of the GoL project that could be made into components for reuse.