Grammar Based Automatic Web Services Composition Method

With the emergence of technologies and standards supporting the development of web services, more and more services are available on the Internet. But most of the services are single and their functions are simple. To improve the reusability and accelerate application development and provide more powerful functions, it is important to integrate the inter-organizational and heterogeneous services on the Web at the runtime. As an important method for flexible and rapid integration, Web services composition becomes a hot research of complex distributed application in open and heterogeneous environment.Most of the existing projects and frameworks use static modeling method to compose services. However, the Internet is dynamic and the services are changeable, those projects and platforms are not flexible enough. After discussing two major web service composition methods, this paper introduces a method for automatic composition of web services using grammar. The major work and contributions are as follows:First, we propose a method that transforms the service to grammar rules. We use the grammar-transformer algorithm and transform service to grammar rule. The transformation unit is the operation of service. Each operation of a service is transformed to a single grammar rule. After this, the service repository became a set of grammar rules.Second, we prove the User Request. We build a User Request Prover and use the grammar rules in the grammar rules repository to prove the user request (We improved the grammar analysis algorithm to support User Request Prover).Last, we automatically generate the composite service. As the user request is proven, we generate the optimal path for each output object of user request, then we compose the optimal paths to construct a coarse-grain composite service.