Application Research On Method For Refactoring Business Logic

In order to guarantee system run continuously steady and adapt changing requirements, system maintenance became an essential important part of system life cycle. With the development of information infrastructure, as such factors as hardware upgrade and change in manangement requirements, maintainability of software was demanded higher. Softeware maintenance as a practical subject was paid attention by more and more experts and engineers.During the maintenance of the software, such factors as changes in requirements will lead to the modification of software code even design. In this process, the design of software may no longer meet the new requirements and may decay, so here refactoring should be applied to adjust the code to prevent software design from continuing to decay and eventually make its structure well.Firstly, domestic and overseas research is summarized respectively in detail. On the basis of that, the scope and objective of this thesis are presented. Secondly, Refactoring technology is further studied, and related concepts such as architecture, framework and pattern are elaborated and then Relationship between refactoring and pattern is discussed. Next, aimed at the problems which are unlegible layer structure, unrational data access layer and chaotic RFID card access layer existing in MIS for Passenger Transportation Safty, the analysis is carried out in the thesis, and the three steps of refactoring business logic layer which are Separate Domain from Presentation, Convert Procedural Design to Objects, and Refactor to Pattern, are summarized and proposed. The core business of MIS for passenger transportation safety, Normal Dispatch module is refactored in the method proposed by this thesis. In first step the business logic of Normal Dispatch is separated from presentation and contained in the business logic class Dispatch. In second step the Procedural Design in the class Dispatch is converted to Objects Design and refined to a series of related classes. In third step Abstract Factory, Command, Observer and Template Method Design Pattern are introduced to optimize Objects Design. Also data access layer and RFID access layer associated with business logic layer are refactored. Finally, the design and benefit of overall architecture, data access layer and presentation layer of MIS for Passenger Transportation Safty refactored are presented.Amied at refactoring business logic layer, three common steps are proposed in the thesis. Practice has proved that it makes business logic layer of MIS for Passenger Transportation Safty which eventually become a three-layer system which has clear structure and well scalability separeated from presentation layer by applying thses steps.