Agile Software Development

The agile software development method is a newly arisen kind of software development method in resent years. It is a lightweight method. This method is against the traditional, large, heavy process, emphasizes the communication of people, and advocates that high quality codes should replace the documents. Agile method is able to adapt to requirement change and develop the software quickly. This sort of development method improves the efficiency and resolves some problems which have existed in traditional development methods. Agile method is applied rapidly.This paper studies the class design principles and patterns, researches the component design principles, and introduces the iterative development method in agile method. And then apply this principles, design patterns, and method to a practical application. In development of chemical software named CHEM, iterative method is used to develop and realize the three function models: the Sample Collection, the Quantitative calibration and the Product Model step by step. In each iterative phase, the appropriate principles and design patterns are chosen to realize all the classes. And then, these classes are packed to different components according to the distribution principles.In development of CHEM, after each iterative phase, the completed classes, modules and components are tested immediately, and integrated continuous into system function. And during these periods, CHEM is useable. As soon as possible to delivery the first useable software version to customers, we can respond the feedback of customers. Many defects are found and then modified. The subsequent iterative phases is continued, tested and integrated into system functions. Because of the character, agile development method can reduce the project risk and is able to adapt to requirement change and develop the software quickly.In development of CHEM, the chemical algorithms written by professional chemical numeric processing software are packed into a COM component packages. Visual studio C#.NET is used to design windows UI (user interface), and the chemical algorithms in COM components are called to process the data procedures.