The Research And Implementation Of Adjustment Execution Mechanism For Self-Adaptive Service Composition

Adjustment is necessary for service composition to handle the exception caused by the environmental change. QoS requirement varies in different instances of the same service composition, that resulting in different adjustment action to each service composition instance when handling the exception caused by the environmental change. The existing adjustment execution methods seldom provide ability to adjust each instance with different adjustment actions, leading to maladjustment of service composition instance to its environment. Establishing a adjustment execution method with such ability is a hotspot in self-adaptive service composition.In this thesis, an adjustment execution mechanism for self-adaptation service composition, which based on primitive, is proposed to meet the demand. In this mechanism, primitive is used to describe the adjustment action, which separates the business process and the adjustment process. First, adjustment primitive is designed to describe the adjustment action by analyzing the adjustment execution method based on activity replacement. The adjustment primitive is defined with source service composition, object service composition and the parameters match rule. Then, the adjustment execution mechanism based on primitive is proposed and an execution engine of service composition based on it, which supporting adjustment in self-adaptation for service composition, is established based on the mechanism. In the next step, a state-driven execution method of primitive is found with the concepts of execution object, environment state and state space. The execution engine is built, and experiments verify the validity of the mechanism as the end.