A Model Of Application Integration Based On Web Services

The development of e-business has been changing the business patterns of enterprises. Now enterprises are faced with complicated and changeful business environment, when Internet tighter and tighter couples them with their customs, providers and partners. Each enterprise demands urgently for an application integration system that has full functions and well performance, and can be used to optimize enterprise resources utilization, to suit to frequent application modification, and to improve response capacity. Analyzing the existing point-to-point and message agent-based integration patterns, we classify them as proprietary methods that are tightly coupled and hard to expand. So we put forward a new integration model based on web services architecture, which solves uniformly integration problems among applications within enterprise and between them with a standard and opening, platform and language independent technology.The web services-based application integration model builds on the .NET platform, and locates inside the enterprise firewall to provide secure access to web services. The model corresponds to the principle of the web services architecture that includes three roles. In the model, we encapsulate functions of enterprise applications into web services and use them as service provider, and we use back-end applications that access web services to act as service requestor, and implement e-uddi as private service registry which support to service publication and discovery, dynamic integration and fault-recovery. The model also reflects the polymorphism of web services protocol stack. We can achieve the interoperability and application integration between different heterogeneous platforms by applying the general WSDL/SOAP/HTTP stack, or we can optimize local integration performance by using proprietary LAN-stack in some special case.In the process of constructing web services, we utilize the COM-Interoperability and the platform-invocation services of the .NET framework to access the COM components and DLL libraries implemented by enterprise applications. We expose their functions and data to other applications by encapsulating them as web services. Similarly we use Java API for web services to encapsulate Java applications. By means of the excellent interoperability of web services, we can integrate loosely all the heterogeneous applications whether they are based on .NET or J2EE.By virtue of its opening standards, web services provide a unifying programming model and integration platform, with which we can use existing technologies and tools, so that application integration inside and outside the enterprise can be done with a common approach. That is the design idea of our model.