The Internet is revolutionizing business by providing an affordable and eficient
way to link companies with their partners as well as to their customers. However,
there are certain issues that reduce the effectiveness of the Internet. Among those
issues, incompatible applications and frameworks that cannot interoperate or that
cannot exchange business data have become a major concern. The Web Service is
a new e-business model that is expected to change in a way in which the business
applications are developed, integrated, and interoperated. Web Services are
self-describing and self-contained. A Web Service is a modular application that is
accessible over the web. It is exposed as an XML interface, and it communicates with
other services by using XML messages over standard Web protocols.
W3C, one of the standard bodies of Web Services deines a Web Service as a software
system designed to support interoperable machine-to-machine interaction over a
network. It has an interface described in a machine-processable and human readable
format called WSDL (Web Services Description Language). Other applications
communicate with the Web Service in a manner prescribed by its description using
SOAP (Simple Object Access Protocol) messages, typically conveyed using HTTP
with an XML serialization in conjunction with other web-related standards.
The Web Service, a very well known open technology standard provides a number
of beneits as listed below:
1. Increase competition among vendors, resulting in lower product costs.
2. Ease transition from one product to another, resulting in lower training costs.
3. Increase the ability for parties to interoperate, resulting in lower
maintenance costs.
4. Ensure a greater degree of adoption and longevity for a standard. A large
degree of usage from the vendors and the users leads to a higher degree
of acceptance.
One can argue that the Web Service concept is a logical evolution from an
object-oriented system to a system of services. As in an object-oriented system, some
of the fundamental concepts in Web Services are encapsulation, message passing,
and dynamic binding. However, the service-based concept is extended beyond
method signatures. The information as to what the service does, where is it located,
how it is invoked, the quality of service, and the security policy related to the service
can be published in the service interface (WSDL).
