A Web Service is a software program that exposes a coherent functionality via an interface described in a machine-processable format (e.g. WSDL) and supports inter operable machine-to-machine interactions with other programs via XML-based messages (e.g. SOAP) conveyed using Web-related standards (W3C, 2004a).
A primary contribution of Web Services toward conquering the limitations of
conventional middleware and proprietary EAI/EDI infrastructures is to enforce
standardization in defining, describing, and discovering services. Such standardization should support interactions with other programs in a peer-to-peer fashion based on middleware protocols within the service-oriented paradigm leading to a design strategy that everything could be exposed and used as a service (Alonso, 2004). The most distinct feature of using Web Services is the designed machine- interpretability supporting a Web Service discovery and invocation by other software systems, and consequently interaction with the service. The foundation of the machine-interpretable Web Services is to express the knowledge required for properly interacting with a Web Service in a format that can be processed automatically by any service requester. A requester analyzes a service description to determine whether a Web Service is qualified for fulfilling a given request and to acquire the details of how to use a Web Service. The rest of this section contains a brief background to Web Services and their three main pillars, namely SOAP, WSDL, and UDDI technologies.
conventional middleware and proprietary EAI/EDI infrastructures is to enforce
standardization in defining, describing, and discovering services. Such standardization should support interactions with other programs in a peer-to-peer fashion based on middleware protocols within the service-oriented paradigm leading to a design strategy that everything could be exposed and used as a service (Alonso, 2004). The most distinct feature of using Web Services is the designed machine- interpretability supporting a Web Service discovery and invocation by other software systems, and consequently interaction with the service. The foundation of the machine-interpretable Web Services is to express the knowledge required for properly interacting with a Web Service in a format that can be processed automatically by any service requester. A requester analyzes a service description to determine whether a Web Service is qualified for fulfilling a given request and to acquire the details of how to use a Web Service. The rest of this section contains a brief background to Web Services and their three main pillars, namely SOAP, WSDL, and UDDI technologies.
