High 'Standards'

Web Services have played a major role in enabling the new generation of
Internet-based applications. There are countless examples of applications that
have been made possible by Web Services-automated business transactions and
direct (non-browser) desktop as well as handheld device access to reservations,
stock trading, and order-tracking systems. Web Services allow applications at
different network locations to be integrated to functions as if they were part
of a single, large software system.

Web Services are becoming very important, but without standards support to
ensure interoperability, they're worthless. Web Services platforms must
conform to industry standards such as the Web Services Interoperability
Organization's (WS-I) Basic Profile 1.0 (a set of rules specifying how to
implement key Web services specifications). WS-I is an open industry
organization chartered to promote Web services interoperability across
platforms, operating systems and programming languages.

Standardization is important so that customers won't be locked into a
particular vendor's implementation. So, several key standards have emerged.
Some of the prominent ones being XML (Extensible Markup Language), WSDL (Web
Services Definition Language), SOAP (Simple Object Access Protocol), and UDDI
(Universal Description, Discovery and Integration). Among these, XML has emerged
as a flexible way to create standard information formats and share both the
format and the data on the World Wide Web. The portability and extensibility of
both XML and Java technologies make them a natural match for the creation of
applications-where different classes of clients consume and generate
information that is exchanged between different servers running on multiple
system platforms. SOAP is the standard messaging protocol used by J2EE Web
Services, and is the de facto standard for Web Services. Its primary application
is Application-to-Application (A2A) communication. Specifically, it's used in
Business-to-Business (B2B) and Enterprise Application Integration (EAI), which
are two sides of the same coin: both focus on integrating software applications
and data sharing. UDDI creates a platform-independent, open framework for
describing services, discovering businesses, and integrating business services
using the Internet.

Web Services Description Language (WSDL) is the current proposed standard to
describe a Web Service, an Interface Definition Language (IDL) service based on
XML that defines the service interface and its implementation characteristics.
WSDL is referenced by UDDI entries and describes the SOAP messages that define a
particular Web service.

Web Services are also finding increased utilization due to technologies like
Grid Computing. These technologies are providing improved utilization of
existing heterogeneous resources while increasing productivity and collaboration
for valuable technical professionals. Increased levels of integration,
standardization, and higher levels of abstraction are finally allowing
management of services, rather than individual hardware, operating system, and
application platforms.

Again, one of the important parameters that CIOs must look for is
interoperability. Your Web Services platform must enable you to quickly design,
develop, test and deploy web services and clients that fully interoperate with
other Web Services and clients running on any platform. Today, complete
interoperability is possible due to a standardized XML-based data stream.

Open, interoperable systems, could one day enable software to run on any
operating system. After all, Web Service emerged as the solution for providing a
standard way to retrieve data without proprietary software and hardware. A Web
Service cornerstone is its ability to transfer data from the provider to the
consumer, or someone who requests, using the ubiquitous HTTP protocol for an XML
format. Formatting the data in XML greatly facilitates raw data's conversion
into a renderable format. Extensible Stylesheet Language Transformations (XSLT)
perform the transformation rather easily.

Today, support for Web Service is considered to be of utmost importance.
Finally, a standards-based web services model, if used effectively, has the
capacity to deliver extra ordinary benefits to any enterprise-big or small.

With contribution from editorial advisor Anil Valluri, director,
Client Solutions Organization, Sun Microsystems India

Technologies of Web Services

The technologies that form the foundations of Web Services are SOAP, WSDL and
UDDI.

SOAP Simple Object Access Protocol is an XML-based mechanism for exchanging
information between applications within a distributed environment. This
information exchange mechanism can be used to send messages between
applications, and more specifically, can be used to implement remote procedure
calls (RPCs)

WSDL Web Services Description Language is an XML-based language for
describing Web Services. Through a WSDL description, a client application can
determine the location of the remote Web Service, the functions it implements,
as well as how to access and use each function. After passing a WSDL
description, a client application can appropriately format a SOAP request and
dispatch it to the location of the Web Service

UDDI Universal Description, Discovery and Integration is a specification for
a registry of information for Web Services. UDDI defines a means to publish, and
more importantly, discover (or search for) information, including WSDL files,
about Web Services.