Green Web Services Integration and Workflow Execution within Next Generation CEMIS

Service-Oriented Architectures

This section illustrates the main service orientation concept. The OASIS service-oriented architecture (SOA) Reference Model group defines SOA as follows: “SOA is a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. It provides a uniform means to offer, discover, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations” (MacKenzie, Laskey, McCabe, Brown, & Metz, 2006). Several technologies are used to realize SOA but Web Services are accorded the most common ones. A Web Service as defined by the W3C consortium is “a software system designed to support interoperable machine to machine interaction over a network” (Booth et al., 2004). In concept, there are three main components in SOA, namely:

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  Service Provider: It creates a Web Service and possibly publishes its interface and access information to the service registry;

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  Service Registry: Is responsible for making the access information of both Web Service interface and implementation available to any potential service requester, and categorizing the results in taxonomies. The Universal Description Discovery and Integration (UDDI), defines a way to publish and discover information about Web Services;

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  Service Consumer: The service consumer (Web Service client) locates entries in the service registry using various find operations and then binds to the service provider in order to invoke one of its Web Services.