Research On Requirement-Driven Self-Adaptive Web Services Composition

The necessity of the study of Web services composition is highlighted, since the single function and the simple structure of Web services can not meet the increasingly complex business requirements. However, in the process of services composition, the composition is facing with many problems caused by the change of runtime environment information and users’requirement information. In order to make Web services composition can adapt to dynamic changes of external environment and users’requirements, self-adaptive mechanism is introduced into Web services composition. According to adaptive strategies, by sensing the changes of external environment and users’ requirements, self-adaptive services composition system can adjust its own behaviour independently to respond the perceived changes of external environment and users’ requirements. At the same time, with the expansion of services composition scale and the increasingly complex and continuous growth of system requirements, the development of system faces in the new challenges. Therefore, requirements engineering concepts have been introduced into the field of services composition. Combining requirement modeling technology with sef-adaptive Web services composition technology, research on requirement-driven self-adaptive Web services composition has the important practical significance.According to the current researches of Web services composition, on the basis of learning the knowledge of relational theory, combining with the requirement modeling technology, this paper presents a requirement-driven self-adaptive Web services composition framework, and introduces the implementation principle and the process of the framework. Firstly, the model of users’ functional requirements and non-functional requirements is constructed using I*framework and its extended semantic. Then the requirement model is transformed to the abstract Web services composition model, and the abstract Web services composition model is mapped to the specific Web services composition model described by CCML. The main function modules of the framework, including execution engine, discovery engine, monitor and planner, etc., are designed and implemented. The adaptive mechanism of the framework is also introduced in detail. Finally, a travel Web services composition examples are given. Through the simulation of the implementation process, the feasibility and effectiveness of the requirement-driven self-adaptive Web services composition framework is verified.