- Web Services as B2B Evolution: From XML to Web Services
- Web Services as Enabler for Business Innovation—Interoperability
- Web Services as Distributed Component Model
Web services has been a buzz word for some time now. For many of you developers who read this article, Web services may already be a reality. The second edition of our book, XML and Java: Developing Web Applications, has chapters on SOAP, UDDI, and WSDL, which show you how to use these technologies in real-world applications. On the other hand, I admit that there are still a number of people who are skeptical about Web services. What is the value of Web services? Why do we care?
It seems that there are several different views on Web services. Depending on your background, Web services could be the following:
a natural evolution of XML-based business-to-business (B2B) integration
a new way of integrating business processes
a redefined set of distributed programming model
In this article, I try to give you a better sense of what Web services is by positioning it in these different perspectives.
Web Services as B2B Evolution: From XML to Web Services
XML was originally designed as a lightweight version of SGML, a markup language for structured documents. As soon as XML 1.0 Recommendation was released in February 1998, however, many people recognized the possibility of using XML as a language framework for B2B data interchange between business applications. By defining industry-specific vocabularies, XML has served as a common data format for connecting, or integrating, applications. Many industry forums and consortia were formed to define such vocabularies. See http://xml.org/ for a list of XML vocabularies.
Although XML provides a firm foundation for designing industry-specific vocabularies for B2B applications, integrating applications requires more than a common data format. For example, how can we exchange XML data between applications? Or how can we find applications? Because there are a number of such common issues, it was a natural consequence to need a common framework for discovering, describing, and invoking applications on top of the common data format.
As such, for most of us who are familiar with XML-based B2B systems, Web services is an evolutionary step toward more dynamic and seamless B2B integration. If you have worked in XML-based B2B systems, I think it should be easy to understand the value of these new standardsUDDI, WSDL, and SOAPbecause they give us a standard way to implement the fundamental functions that are needed for discovering, describing, and connecting to other applications on the Internet (which would otherwise need to be implemented in an ad-hoc manner).