The Web services architecture

The Web services architecture is based upon interactions between three components: a service provider, a service requester, and an optional service registry.

The service provider
The collection of software that provides a Web service. It includes
  • The application program
  • The middleware
  • The platform on which they run
The service requester
The collection of software that is responsible for requesting a Web service from a service provider. It includes
  • The application program
  • The middleware
  • The platform on which they run
The service registry
A place where service providers publish descriptions of the services they provide, and where service requesters find them.

The registry is an optional component of the Web services architecture, as there are many situations where service requesters and providers can communicate without it. For example, the organization that provides a service can distribute the service description directly to the users of the service, using an attachment in an e-mail, or a download from an FTP site, or even a CD-ROM distribution.

Figure 1. Web service components and interactionsThe interactions between the Web service components. These are described in the text.

CICS® provides direct support for implementing the requester and provider components; you will need additional software to deploy a service registry in CICS. But because the Web service architecture is platform independent, you can, if you need a service registry, deploy it on another platform.

The interactions between the components involve the following operations:
Bind
The service requester uses the service description to bind with the service provider and interact with the Web service implementation.
Publish
When a service registry is used, a service provider publishes its description in a registry so that the requester can find it.
Find
When a service registry is used, a service requester finds the service description in the registry.