Quality Assurance for Component Based Software Development Cai

Quality Assurance for Component. Based Software Development Cai Xia (Mphil Term 1) Supervisor: Prof. Michael R. Lyu 5 May, 2000

Presentation Outline Introduction Current Technologies for Component Case Study Survey on Software Quality Assurance A draft QA model for Component-Based Software Development Conclusion

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

What is Component-Based Software Development ? Component 1 Component repository Component 2 Software systems . . . Component n assemble select Commercial Off-the-shelf (COTS) components

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 welldefined architecture It communicates with other components by the interfaces

System Architecture Layered Modular Application 2 Application 1 Application 3 Special business components Common components Basic components Application Layer

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

CORBA is an open standard for application interoperability 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

COM Introduced in 1993 Platform-dependent (Windows, Windows. NT) Language-independent Defines how components and their clients interact directly and dynamically Enables on-line software update and crosslanguage software reuse

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

Java. Beans/EJB Java. Beans for client-side component development Enterprise Java. Beans for server-side component development Platform-independent Language-dependent (Java) Enables scalable, secure, business-critical, multiplatform, reusable components

Java. Beans/EJB 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

Case Study: IBM San. Francisco Objective: 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

San. Francisco Infrastructure

Software Quality Assurance (SQA) Process-oriented (Software Quality Engineering) Objective: procedures, techniques and tools standard: ISO 9000 -3, CMM Product-oriented (Software Quality Control) Objective: software product delivered method: testing tools, metrics

Software Quality Standard & Model ISO 9000 (International Organization for Standardization) development and management process CMM (Software Engineering Institute SEI) five levels of increasing process maturity HKSQA Model (Hong Kong Productivity Council) a framework of local software standard practices

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

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

Testability Factors in OO Systems

Example Metrics for OO Software

QA for Component-Based Software How to certify quality of a component? How to certify quality of a componentbased software system?

Component vs. Object: Defined at a low level Component: higher-level entity Object: multiple inheritance model inherent dependency Component: multiple interfaces flexibility

Life Cycle of A Component

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

Open Problems About QA for CBSD Identification of the QA characteristics Well-defined Standards Models Metrics Testing tools

Quality Characteristics of Components Functionality Interface Userability Testability Modifiability (Maintainability) Documentation Fault Tolerance (Reliability)

A Draft QA Model for CBSD Component System

Main Practices Component requirement analysis Component development Component evaluation Component customization System architecture design System integration System testing System maintenance

Process Overview Diagrams Component Requirement Analysis

Process Overview Diagrams Component Development

Process Overview Diagrams Component Evaluation

Process Overview Diagrams Component Customization

Process Overview Diagrams System Architecture Design

Process Overview Diagrams System Integration

Process Overview Diagrams System Testing

Process Overview Diagrams System Maintenance

Conclusion and Future Work QA for CBSD should contain two different parts: component and system Materialize the draft model Evaluate existing testing tools for specific component technology, e. g. Java. Beans Metrics

Q & A Section