Cloudware Technologies - Guide to Cloud Computing for Business and Technology Managers - page 313

discussed in conjunction with Web Services, these two are not synony-
mous. In fact SOA can be implemented without the use of Web Services, for
example, using Java, C#, or J2EE. However, Web Services should be seen as a
primary example of a message delivery model that makes it much easier to
deploy an SOA. Web Services standards are key to enabling interoperability
as well as key issues including quality of system (QoS), system semantics,
security, management, and reliable messaging.

15.3.1 Operations in the SOA

SOA enables three primary operations; these are publication of the service
descriptions, finding the service descriptions, and binding or invocation of
services based on their service description. These three basic operations can
occur singly or iteratively. A logical view of the SOA is given in Figure 15.2.
This figure illustrates the relationship between the SOA operations and
roles. First, the Web Services provider publishes its Web Service(s) with the
discovery agency. Next, the Web Services client searches for desired Web
Services using the registry of the discovery agency. Finally, the Web Services
client, using the information obtained from the discovery agency, invokes
(binds to) the Web Services provided by the Web Services provider.

15.3.1.1 Publish Operation

Publishing a Web Service so that other users or applications can find it actu-
ally consists of two equally important operations. The first operation is
describing the Web Service itself; the other is the actual registration of the
Web Service.
The first requirement for publishing Web Services with the service regis-
try is for a service provider to properly describe them in WSDL. For proper

Service

Service
provider

Service
description

Publish Bind

Service
description

Service
registry

Service
client

Find

FIGURE 15.2
Web Services Operations.