Research On Techniques For SOA Integration Based On DDS

With feature of loose coupling, SOA can help enterprises to add new services or upgrade existing services in the modular way to achieve efficient use of existing resources. As a kind of SOA implement technology, Web Services adopt SOAP messages based on XML to transmit data between service consumer and service provider, resulting in large resource consumption and long service invocation response time. DDS has been widely applied to national defense and other important application fields with its efficient data transmission ability and rich QoS support, and has become an ideal candidate technology to improve Web Services.In this thesis, an integration scheme adopting DDS to transmit data between service consumer and service provider is proposed by analyzing the communication characteristics of DDS and the framework of Web Services. With the scheme, applications can be encapsulated as services and the requirements of real-time communication between these applications can be meet. Based on the scheme, service selection mechanisms and algorithms in Web Services are improved. The main contribution of this thesis is as follows:1. An integration scheme named DWS which adopts DDS to transmit data between service consumer and service provider is proposed, including the framework of Web Services based on DDS and the mapping solutions of communication and data models between DDS and Web Services. Based on DWS, a scheme named DWS-LocalCache is presented by using the discovery protocol of DDS and the advantage of Publish/Subscribe mechanism, which can improve the efficiency of service invocation and reduce the service call response time.2. Two kinds of service selection schemes named SingleRank and MultiRank are proposed based on DDS Privilege QoS. With SingleRank scheme, ranks of multiple service providers are calculated by AHP and TOPSIS algorithms, then are mapped to DDS Privilege QoS values, which are used as the basis of services choice. The MultiRank scheme is designed for the scenario of multiple service consumers. It can meet the demand that most of the service consumers choose their optimal service by considering user preferences and objective factors of candidates of service providers.3. Based on DWS and MultiRank, a Web Services prototype based on DDS is desigened and implemented using gSOAP and information integration management software. Then tests have been conducted. The results show that the proposed DWS scheme can greatly reduce the service response time and improve the service invocation throughput. The proposed MultiRank service selection scheme takes multiple service consumers with different QoS requirements into account, and can make optimal choices for most service consumers in most cases.