Introduction to service composition Sample Clauses

Introduction to service composition. ‌ Service-oriented computing (SOC) is the computing paradigm that utilises services as fundamental elements for developing applications [83]. In the SOC environment, service-based applications are developed as independent sets of interacting services offering self-describing standardised interfaces to potential service consumers. Services perform functions – from simple requests to complicated business processes. Organisations can expose their core competencies in the form of services over the Internet (or intranet) using standard (XML-based) languages and protocols [82]. Web Services are the current most promising technology based on the concept of SOC, offering significant benefits in flexibility, ease of use, and reuse as well as providing a way to develop an SOA incrementally, although an SOA contains more than Web services. Web services technologies enable making connections among heterogeneous software that each performs a discrete function. By wrapping these softwares with Web service interfaces, they can communicate and interoperate to perform a complex business process. Technically, the term “Web services” describes a standardised way of integrating Web-based applications using the Extensible Markup Language (XML), Simple Object Access Protocol (SOAP) [36], Web Service Description Language (WSDL) [20, 22] and Universal Description, Discovery and Integration (UDDI) [23] open standards over an Internet protocol backbone. For example, if a programmer wants to make a Java program accessible to other applications deployed over the Internet, the programmer can publish the program as a Web service in a UDDI server, with its interface (some of the method names and associated parameters) detailed with a service description written in WSDL. Then the application builders who need the Java program can find it in the UDDI server and invoke it through sending SOAP messages typically conveyed using HTTP. 2Figure 1.1 presents the architecture of Web services [57]. By adopting the Web services technology, heterogeneous applications distributed across the Internet can be integrated in a uniform and standardised manner because Web services provide the following benefits: • Decoupling of service interfaces from implementations and platform considerations; • Enablement of dynamic service binding; and • Increase in cross-language and cross-platform interoperability.