Research And Implementation Of Cycle Matching For Homogeneous Symmetric Publish/Subscribe System

A publish/subscribe system is a distributed middleware system that the producers and the consumers of information can communicate with each others. There exists a class of applications, such as Barter Services, Item Exchange, etc., where publisher needs the capability to select subscribers besides publishing information, and the role of publisher and subscriber is symmetric, such kind of publish/subscribe applications is called homogeneous symmetric publish/subscribe system.In homogeneous symmetric publish/subscribe application, besides one-to-one swap, exchange can occur between more than two subscriptions, which is called cycle matching. The cycle matching provides more exchange candidates for users to choose and improves the number of successful exchanges.The previous work is focusing on finding cycle matchings on a pre-built graph. There is only few work on the topic about how to find cycle matching dynamically, which is essential for Pub/Sub applications, and so it is the the focus of this paper. To solve this problem, this paper first design the model of cycle matching, then propose a dynamic cycle matching algorithms, and prove that they can work correctly. Further, in order to save the space used to keep middle results, we propose a threshold strategy, which can optimize the result well.Publish/subscribe system provides an information exchange platform for users, how to make the maximum number of users participated in matches simultaneously, and at the same time take the satisfactory degree of the subscribers involved in matches into account, is one of the key issues should be considered in publish/subscribe system. Combining the system’s view with the subscriber’s view in Online Barter-exchange market, this paper has proposed and implemented the system optimal algorithm considering the customer satisfaction degree, proved the validity of the algorithm, further, according to the dynamics of publish/subscribe system, the dynamic updating algorithm based on threshold has been proposed.The proposals are evaluated in a simulated environment. The evaluation results show that, the proposals have good scalability and maintenance performance. As a result, they are suitable for homogeneous symmetric publish/subscribe system.