Research On Shipped Code Reusing In Self-Extensible Middleware

Database middleware systems are used to integrate collections of data sources distributed over a computer network. It is the most widely used and maturest middleware. The function is seperated from the data by the Database middleware,and the function is wrapped by the classes.The capability of reuse is improved. However, in order to optimize the query operation, Some Database middleware such as MOCHA ship part of codes to the distant sites which are close by the database. These shipped codes can't be reused any more.To solve these problems discussed above, this paper is to import the reuse mechanism to the metadata-driven database middleware.l)In order to implement the code reuse, the paper analyses the factors which affects the code reuse, and evaluates the code reuse degree by a criterion. In order to evaluate the code reuse degree dynamicly, the using degree is imported. 2) Because reuse mechanism may cause the file naming confliction. The paper uses the Naming Space to avoid such confliction. 3) In order to implement the reuse, paper designs the consistency maintained plan and the deletion plan, it also designs the code shipping algorithm.Finally, the paper discusses the application of this model in the JangSu Water conservancy system and evaluate its feasibility and efficiency by comparing and testing. It provides a model which can be referenced in this domain.