Research On Runtime Monitoring For Composite Web Services

With the rapid development of the productivity and modern science and technology, software has penetrated into almost every area of society and played an important and irreplaceable role. However, as the size and complexity rise, the software fault and failure problems become more and more serious, which have posed great impact on people's lives and even the national security. As a result, the research of assuring software running safely and reliably draws wide attentions. To solve this problem, researchers have proposed a variety of solutions, such as model checking, theorem proving, software testing, runtime monitoring, and so on.Meanwhile, with the rapid development of network technology, the internet deeply affects people's production and life, which causes software to be more open and distributed. As a result, there is a variety of new forms of software appearing, and web service is the most representative one of them.Web services are considered as self-contained, self-describing, modular applications that can be published, located, and invoked across the web. Several autonomous web services can be combined to provide more powerful composite web services depending on the application needs. Web services are loosely coupled and highly dynamic, so there will be many unpredictable changes in basic services, such as version upgrades and so on, which will affect the quality and function of the entire service. Programmers can ensure the combination of services to be correct through static testing and verification techniques, but its actual execution behavior may still be inconsistent with the properties of service requirements, so it is necessary to monitor the composite web services in runtime.This dissertation first analyses the traditional software runtime monitoring technology, summarizes the basic principles of runtime monitoring and proposes a basic view of the monitor, which provides a basis for research on runtime monitoring for composite web services; second, this dissertation studies theory and technologies on composite Web services, through which we are in depth knowledge of them; then, with the introduction of event calculus, which is a theory for reasoning about actions based on first-order predicate calculus, this dissertation builds a property specification model of the composite web services system, which defines the events and flow of the system and expresses the behavioral property completely; next, through the study of BPEL4WS technology, this dissertation designs a series of conversion templates from BPEL4WS events to event calculus and implements a algorithm which could convert the BPEL4WS description of a service composition process to be a property specification in event calculus; at last, this dissertation proposes a monitoring framework for composite web services and shows the monitoring algorithm.