Multi-Layer Reconfigurable Architecture For Web Application Server

With the explosive development of Internet, software platforms for Web applications have been the mainstream category in software industry. The core and key element of the platform is Web Application Server (WAS), which resides at the middle tier in the three-tier client/server architecture. WAS solves the problems in applying traditional middleware to Web computing environment and provides a series of run-time services to support for Web applications. WAS has a huge potential market, and it can be used to to build enterprise management system, e-commerce, and e-government system.Attention to the new category of middleware has been drawn from the academia and software industry after it was born. It is considered to be one of the most exciting milestones of enterprise software technology since the relational database and has become very popular in the last few years. To meet the urgent need for WAS and cater for the mainstream trend of Web applications, this thesis outlines some key issues in developing WAS.To cater for an increasingly diverse range of QoS demands, a dynamic reconfiguration model for WASs, referred to as DR, is presented, and a run-time reconfiguration algorithm is designed to drive the system to be reconfiguration-safe state for the purpose of preserving the reconfiguration consistency. A multi-phase reconfigurable architecture is introduced on the base of DR model, supplemented by the marriage of microkernel technology and reflection technology. In the architecture, WAS is very open and flexible to support deployment-time configurability and run-time re-configurability.A J2EE application server is implemented. The approaches and solutions the thesis proposed are applied to the design and implementation of the server product. At present, it has passed all the test cases in Sun PetStore test suite. All the stressing test cases in ECPerf benchmark have been passed also. It can be used widely in small and middle-sized enterprises.