NonStop Systems Introduction for H-Series RVUs

The Application Server Environment
NonStop Systems Introduction for H-Series RVUs— 540083-001
3-34
Web Service Providers
As the figure shows, the basic Web services architecture consists of three main
components:
•
The services
•
The service requesters, or clients
•
The services provider
We now examine these components in greater detail.
The services are software modules that perform common business functions. For
example, an application might be built from Web services that check a customer’s
credit, charge the customers account, and set up shipment with a shipping company.
The service requesters can be applications or other Web services. Clients can be
written in any language, such as C, C++, Java, and Microsoft Visual Basic.
The services provider handles communications between the requesters and services.
The services provider is responsible for interpreting a client request, invoking a service
on the target server, and receiving the service response and creating a response to be
sent to the client. The services provider provides a standard way of communicating
between clients and services. In the HP implementation, the services provider resides
on a NonStop system.
The figure also shows a component called the Universal Discovery Description and
Integration (UDDI) registry. This is a file system where service providers can
“advertise” their services. It is analogous to the yellow pages of a telephone directory,
where potential clients can easily locate the services they need. The UDDI registry is
an XML file that describes a business and the services it offers. As with traditional
yellow pages, you can search for a company that offers the services you need, read
about the service offered, and contact someone for more information. The UDDI
registry makes the services visible and advertises them to potential clients. Another
service or application can locate and request a service by querying the UDDI.
The UDDI registry is not an essential part of a Web services solution, and is not always
present. For example, available Web services may be known within an enterprise, thus
obviating the need for a UDDI registry. Or the Web services might be published in a
proprietary registry.
Web Service Providers
Examples of commonly used Web service providers are BEA WebLogic Server
(described later in this manual) and Simple Object Access Protocol (SOAP). Each of
these products takes full advantage of the scalability, fault tolerance, and availability of
the NonStop systems. Clients of each of these Web service providers can be written in
any language, such as C, C++, Java, and Microsoft Visual Basic.
SOAP is an XML-based protocol that uses the hypertext transfer protocol (HTTP) for
communications. SOAP provides a way to communicate between applications running
on various operating systems, with different technologies and programming languages.
SOAP has been implemented on many different systems, which means that SOAP can