Research On Object Caching & Consistency In Web Application Server

Web application server provides runtime-integrated services such as naming service, security service, transaction management, load balancing, fault tolerance etc, for transactional web application. High-speed caching for data in the middle tier (i.e. EJB objects) is needed to make better use of system resources, improve scalability and overall performance of the application server. Particularly, clustered application servers need to support the load balancing and fault tolerance of EJB. So object cache must solve problems in system scalability, data integrity, data consistency and data fault tolerance etc. The research of this thesis will focus on the key technologies in object cache and consistency of EJB component in web application server.On the one hand, this thesis provides solutions for the issue of EJB object cache and its consistency. Pooling is used to implement the object cache for stateless bean, in which small amount of bean instances are arranged to serve method invocations from multiple clients. Caching technologies together with pooling are used to implement the object cache for stateful bean with persistence technology to ensure the cache consistency.On the other hand, research is conducted on object cache and consistency of EJB component in clustered web application server. A Clustered Cache Service Framework is implemented to solve the problem of object cache and consistency in cluster environment by adding Replicated Cache Service and Distributed Cache Service on top of object cache in single application server. A Read-through/Write-behind cache model that enables highly efficient data storage is also implemented in the framework.