B2B Integration : A Practical Guide to Collaborative E-commerce

Service
Provider
PublishJF ^k Bind
c&rui*"-^ Service i
5JJJU |^WBM»«MB^ Rec|uester !
Find
Figure 11.1. — SOA model
Web Services 327
services by communicating with the actual service providers. In most
cases the invocation would be remote over the Internet, but it is also
possible that the invocation of the service is local over the intranet,
which means that the requesting company is also the service provider.
The three most basic operations through which the SOA participants
interact are:
• Publish — It allows the service provider to publish its services and
interface requirements with a service broker. WSDL (Web services
description language) is an XML-based language used to perform the
operation of describing the interface of Web services which are then
published using UDDI.
• Find — This operation allows a service requestor to locate, search
and discover the services published via a service broker that are
offered in a particular classification or by a specific service provider.
Finding is enabled by the UDDI (Universal description, discovery
and integration) framework.
• Bind — This operation enables a service requestor to actually bind
and use a service provided by a service provider. Binding is enabled
by SOAP-based XML messages.
11.2. What are Web Services?
Web services are URL-addressable, self-contained resources and/or
applications that can be described, published, located and invoked over
a network, usually the Internet. Web services are XML representations
;