1.1.1 The Web Services Phenomenon
In June of 2003, there were more than 113 printed books on Web Services available at Amazon.com, compared to 2 printed books in September of 2001, 45 printed books in March of 2002, and 86 printed books in February of 2003. Do a search on the Web, and you will be faced with a huge collection of articles and Web sites devoted to Web Services. Additionally, there are a large number of printed books available to the Web Services audience about an almost identical subject: WSDL-UDDI-SOAP technology. With all of these resources available, how does one choose the best of the bunch?
Scanning through a few titles on the subject, readers may notice that while there are abundant printed materials on Web Services concepts and SOAP programming. There is a general lack of emphasis on the Quality of Services (or so-called "ilities" such as scalability and availability) and real-life, full-scale implementations of Web Services in the printed media. It is not easy to differentiate market hype from a reliable technology implementation, but this book intends to do so ”differentiate real-life examples from the market hype technology, define the Quality of Services for successful Web Services implementation, and discuss how it is applied to legacy mainframe interoperability and Business-to-Business integration.
1.1.2 The Web Services Evolution
Web Services technology and associated vendor products have evolved greatly over the past few years , from SOAP 1.0 to SOAP 1.2. New related technologies emerge from time to time, such as the earlier releases of the Java Web Services Developer Pack (including JAX Pack) and Apache Axis. Java has become the de facto lingua franca of Web Services. Previously, developers needed to build their own application infrastructure tools to handle security, exceptions, and logging. They also needed to write programming routines to handle message acknowledgement and exception handling routines to ensure SOAP messages were reliably exchanged. Nowadays, new Web Services tools such as Java Web Services Developer Pack and Apache Axis provide many built-in Web Services security features, SOAP messaging capabilities, and SOAP server infrastructure tools. These technologies have almost completely changed the previous Web Services programming model and landscape.
As more developers become familiar with these new enabling Web Services technologies, they need to assemble different infrastructure and application components together in order to provide a complete Web Services solution. Most literature today addresses how to build SOAP programs or lab prototypes , but does not address how to implement a complete Web Services solution to interoperate with legacy mainframe applications or to integrate with a Business-to-Business application. There are also many design elements and considerations for the cross-platform interoperability (such as mainframe interoperability), integration experience (such as cross-enterprise integration), and best practices (for example, architecture patterns) that constitute the bigger picture of Web Services technology implementation. These elements are the extended frontiers of Web Services technology toward a total business solution. This book attempts to explore these frontiers by discussing a structured framework for mainframe interoperability, cross-enterprise integration, and some design best practices.