Model of Variable Granularity Service Composition Based on Event Stream

With the arrival of cloud computing and the internet of things, the difficulty of extracting data from the cloud services is preventing some organizations from adopting cloud computing. At the same time, the number of web services increases dramatically, and the granularity of service is different, so how to choose a suitable granularity service also becomes a problem that needs to be resolved. So a storage strategy for cloud computing services is given and the method based on event stream is used to construct the hierarchal model of services which can provide different functional services or different granularity services to meet the business requirements. Firstly, the storage strategy for cloud computing services is that, when registering the services, the meta-data of services will be extracted and stored into database according to certain structure. Secondly, the Event Cloud can be constructed as the one-way event processing, which provide the raw data for more-way event processing. Then the more-way event processing can construct the hierarchical model of services with certain composition goal. The prototype system has been developed in order to fulfill the application, both human events and RFID events can trigger other events in the cloud events, which can create new business models, improve business processes, and reduce costs and risks.