1. Quality Assurance for Component-Based Software Development
Presented by: Cai Xia
Supervised by: Prof. Michael Lyu
11 April, 2000

2. Presentation Outline  Introduction  Current component technologies
 Case study
 Quality Assurance for component-based software systems
 Conclusion

3. Introduction
 Software systems become more and more large-scale, complex and uneasily controlled
 The most promising solution now is component-based software development approach
 The process of CBSD is totally different from traditional systems
 Quality Assurance is very important for component-based software systems

4. What is Component-Based Software Development ?
Component n
Software systems
Component repository
...
select
assemble
Commercial Off-the-shelf (COTS) components

5. What is A Component?
 A component is an independent and replaceable part of a system that fulfills a clear function;
 A component works in the context of a well-defined architecture;
 It communicates with other components by the interfaces.

6. System Architecture  Layered  Modular Application Layer
Special business components
Common components
Basic components
Application2
Application1
Application3
Application Layer

7. Current Component Technologies
 Common Object Request Broker Architecture (CORBA) from Object Management Group (OMG)
 JavaBeans and Enterprise JavaBeans (EJB) from Sun Microsystems
 Component Object Model (COM) and Distributed COM (DCOM) from Microsoft

8. CORBA(1)  CORBA is an open standard for application interoperability
 V1.1 defines IDL, API, ORB (1991)
 V2.0 defines true interoperability (1994)
 ORB is a middleware that establishes the client/server relationships between objects

9. CORBA(2)  allows heterogeneous environments operating systems
execution environment
programming languages
 allows integration of existing components
 CORBA is widely used in OO distributed systems including component-based software systems

10. COM/DCOM(1)  COM: introduced in 1993
 platform-dependent (Windows, WindowsNT)
 language-independent
 defines how components and their clients interact directly and dynamically
 enables on-line software update and cross-language software reuse

11. COM/DCOM(2)  DCOM: introduced in 1996  extension of COM
 a protocol that enables software components to communicate directly over a network
 in a reliable, secure, and efficient manner
 across multiple network transports, including Internet protocols such as HTTP

12. JavaBeans/EJB (1)  JavaBeans for client-side component development
 Enterprise JavaBeans for server-side component development
 platform-independent
 language-dependent (Java)
 enables scalable, secure, business-critical, multiplatform, reusable components

13. JavaBeans/EJB (2)  efficient data access across heterogeneous server
 faster Java client connections, transaction state management, caching and queuing
 connection multiplexing
 transaction load balancing across servers
 easier modification and maintenance than CORBA or COM/DCOM

14. Case Study: IBM SanFrancisco
 subjective: solving the high cost and low efficiency problems when modernizing or maintaining complex specific software systems
 provides a distributed object infrastructure and a set of application components
 programming language: Java
 platforms: Windows NT, OS/400, AIX, Solaris, HP_UX and Reliant UNIX

15. SanFrancisco Infrastructure

16. Software Quality Assurance (SQA)
 Process-oriented (Software Quality Engineering)
subjective: procedures, techniques and tools
standard: ISO9000-3, CMM
 Product-oriented (Software Quality Control)
subjective: software product delivered
method: testing tools, metrics

17. QA for Object-Oriented Systems
Key concepts in OO Design
 Object
 Class
 Polymorphism
 Inheritance

18. Object-Oriented Design
Method Design
Object Design
Object Definition
Attributes of Objects
Communication Among Objects

19. Metrics for OO Software
Aim at:
 Complexity
 Understandability
 Maintainability
 Reusability
 Testability

20. Testability Factors in OO Systems

21. Example Metrics for OO Software

22. QA for Component-Based Software
 How to qualify a component?
 How to qualify a component-based software system?

23. Life Cycle of A Component

24. Life Cycle of CBSD  Requirements analysis
 Software architecture selection, creation, analysis and evaluation
 Component evaluation, selection and customization
 Integration
 Component-based system testing
 Software maintenance

25. Open Problems About QA for CBSD
 identification of the QA characteristics
 well-defined Standards
 models
 metrics
 testing tools

26. Q & A Section