Research And Implementation Of JTang Message-oriented Middleware V3.0

Message-Oriented Middleware (MOM) provides more flexible, efficient, reliable and asynchronous messaging mechanism for distributed applications. Java Message Service, put forward by Sun Microsystems, makes the interoperability among different MOMs to be easy. This paper is based on national supporting plan and key R&D project of Zhejiang province, and also based on existing research results. It is aimed at developing JTang Message-Oriented Middleware V3.0 which focuses on solving the high-performance file-based storage solution, maintaining system load balance by flow control and message cache, bridge different JMS servers by Message Bridge and multi-mode clients.As to durable storage, we propose to store message in files to reach high-performance. It consists of two-level storage model: access interface layer and file storage layer. The feature of the file storage is the implementation of a map (called MapContainer) which has file-store function. In the implementation of MapContainer, we introduce "index file" and "data file", "data file" is used to store the message entity, and "index file" is used to quickly locate "data files". Our solution is proved to supply high-performance, as under the same conditions, the performance of file-based store is almost three times faster than database store.As to flow control and message cache, we proposed to control flow at clients and to cache messages at server to maintain the robust of the server. We classify the memory of server, sending rate of the clients, number of messages to soften every time and so on into several levels. A specific thread is used to collect memory information. The algorithm does flow control and message cache in accord to the memory usage. This algorithm has proved to be very good to maintain load balance of the system under the same conditions.As to the problem to communicate with other JMS servers, we presented message bridge methods. Our methods are designed as the pattern of client, as it can decouple the functions of Message Bridge, and don't have to consider the implementation of the servers at both ends. Besides, we support multi-mode clients including C++ client and Web Service client.