Jms-based Group Communication Middleware

Computer as well as network technologies are now changing working and living manners of people. However, People are not satisfied with the existing communication application of peer to peer. An important trend of computer network technologies is Computer Supported Cooperative Work(CSCW), which possesses a bright future and will become a powerful impetus to the sustainable development of Internet. With characteristics of peer to multi-peer and multi-peer to multi-peer, group communication is a foundation of performing all functions of CSCW, and also a pivotal technology of supporting CSCW. Therefore, group communication has an important status in CSCW application.The paper considers concerned functions of group communication from an application level. Group communication at application level needs not only the support from the essential communication in bottom, but the achievement of communication service at the application level. Current group communication systems have deficiencies in standardization, replaceablity, reliability and efficiency, and thus need to be improved.First, by fully analysing the advantages and disadvantages of group communication and communication mechanism of JMS, the paper brings forward using publish/subscribe of JMS to implement group communication, and accordingly a model of JMS-based Group Communication Middleware (JGCM) is proposed. Second, the frame and contents of group, concerned services are introduced in detail. The former directs catalogue of group, message, message queue, member and member space, while the latter consists of group space management and dependability service in group management, membership space management, view management and failure detection service in membership service, and group communication service etc. Third, according to different demands of communication applications, adopting two different structures in completing group communication are put forward: one is centralized structure, through which non real-time transmission of multimedia information and datainformation, and real-time transmission of data information are implemented by using sending and transmitting functions provided by JGCM. The other is distributed structure, through which direct real-time transmission of multimedia information during clients is completed under the steering of membership service of JGCM by using capturing, real-time transmitting, real-time receiving and playing functions provided in clients. The JGCM inherits the advantages of JMS standardization, replaceablity and reliability, and overcomes the deficiencies such as synchronism exists in communication mechanisms of JMS, thereby which can not only satisfy the demands of group communication, but also assure the communication efficiency. At last, tangible functions of JGCM are implemented by using the key technology such as RMI, thread-pool and JMF. Real-time and non real-time transmission of text, video and audio information are achieved. Rationality and being scientific of JGCM are validated.