Service Orientation Sample Clauses

Service Orientation. The main characteristics of an SOA are the loose coupling between services, the abstraction from technological aspects and its extensibility; features considered essential to cope with distributed developments, heterogeneous technologies integration and to leverage multi-partners collaborations. SOA provides a simple yet efficient way to reuse software artefacts through the concept of standard services that are not bound to each other. Technological abstraction is obtained from using service contracts that are platform-independent. Extensibility is finally reached through service discovery and composition at execution time. Several definitions of the concept can be found in the literature, however for the remainder of this document, only the three following are retained, as they are most relevant to this work: • "A service-oriented architecture is a style of multi-tier computing that helps organizations share logic and data among multiple applications and usage modes" as stated in 1996 by the Gartner group. • "Service Oriented Architecture 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" established in the OASIS reference model. • "SOA enables flexible integration of applications and resources by: (1) representing every application or resource as a service with standardized interface, (2) enabling the service to exchange structured information (messages, documents, "business objects"), and (3) coordinating and mediating between the services to ensure they can be invoked, used and changed effectively". In spite of the absence of a single officially and consensually agreed definition for SOA, three key roles are usually identified: service producers, service brokers and service consumers. The service producer‟s role is to deploy a service on a server and to generate the description of this service (i.e. so-called the service contract), which defines available operations as well as invocation mode(s). This description is published in a directory of services inside a service broker. Thus, services consumers are able to discover available services and to obtain their description by interacting with the service directory. The obtained descriptions can then be used to establish a connection with the producer and to in...