Distributed Architecture Oriented Reengineering For Legacy System

With the progress of time and the development of network technology, some legacy systems used for decades have been out of time in user interface, and the business logic can also no longer meet the changeful requirement of end user. As the result, reengineering to such legacy systems is very crucial.This paper proposed and implemented a solution to reengineer stand-alone legacy system into distributed environment. This solution wrapped the backend data access code and business object code, and exposed them as Web Services according to Service-Oriented Architecture (SOA). At the same time, this solution used Model-View-Presenter (MVP) Architecture to redevelop the frontend user interface, and utilized Web Services request and reply to implement the communication between frontend user interface and backend services. The main work of this paper includes: (1) Introduce MVP architecture, and illustrate how to redevelop frontend user interface. (2) Analyze the ability of working concurrently in distributed system, and raise a Pooling Agent solution to enhance parallelizability. (3) Research on performance problems in distributed environment, and raise corresponding solutions.The solution to reengineer stand-alone legacy system into distributed environment raised in this paper can effectively save human resource and reduce reengineering complexity. By introducing MVP architecture into legacy system frontend redevelopment work, user interface logic code can be separated from view code. As the result, the reusability and testability of business logic code is greatly enhanced, and the efficiency of development and test work is improved accordingly. The distributed system after reengineering will get better parallelity and performance with the adoption of Pooling Agent, Fetching Mechanism and Data Nesting methodology.