Design And Implementation Of Clustering EJB Container For JTang Application Server

Cluster enables a group of loosely coupled computers work together closely at the expense of slower communication between processors. Cluster computing has been increasingly popular in the last decade, for it leads to a cheap way to produce high performance and high availability computers, and cluster technology is being widely used in various kinds of applications especially in middleware.Middleware is intermediary software application which acts as middle layer between systems software and applications;middleware is network connected software that provides services such as identification, authentication, authorization, directories, and security etc. Middleware can reduce development cycle, release the burden of programmers and help developers to build up a flexible, high efficiency, and complex applications. JTang middleware is a light application server accordding to J2EE specification, providing EJB, JMS, JDBC and connection pool, JTS, JNDI, JMS and dynamic deployment services. JTang has a perfect conjunction of Apache Tomcat which supports Servlets and JSPs. Inside the application server, EJB container is a key component and the performance is critical to the quality of services. This paper is intended to design and implement the EJB Clustering EJB Container for JTang Middleware. Firstly, this paper describes the common technology of load-balance and fault torrent in clustering, and analyzes the EJB clustering structure of a popular open-source application JBoss. After that this paper introduces the EJB architecture of JTang EJB container, and an overview function of different component in EJB container is given. Focusing on the high precise and independent load balance, this paper adopts a dynamic load balance strategy and putting the address of target node choosing in client's stubs, and then this paper gives the server's side architecture of EJB cluster. The architecture uses IOC framework and JGroups for base communicating. It provides some service such as Group Service, memory data share Service, replica and recovery Service. This paper devotes a great of material to describing the key process and algorithms of different layer. This paper puts forward the HA-JNDI concept and implementes the memory data share Service.In the last chaper, after listing main Class Diagrams and the user maintaining interface, this paper gives some figures to show the performance test of the implementation. It has been proved to achieve the high performance and high availability objectives, at last this paper concludes the work, and proposes some improvement in the future.