Professional Java SOAP

Web services are currently the main area of growth in the computing industry as a whole, but also more specifically in java. While there are many associated technologies with web services, SOAP has had the most progress and is now adopted as a W3C standard, known as SOAP 1.2 or XML Protocol (XP).

SOAP is exciting not because it is a new concept but because the whole IT industry is agreeing to use it. It can be compared with CORBA, Microsoft's COM+ or DCOM, and Sun's RMI, but unlike those technologies, it is language and Operating System agnostic. You can build your application in any language you wish and, as long as it is connected to the Internet, it will talk to any other SOAP application out there.

The underpinning of the web services explosion is therefore, SOAP. It is used as the underlying protocol in ebXML and every major player in this area (including Microsoft, Sun Microsystems, IBM, BEA, Jakarta) have tools for developing SOAP applications. In addition there are numerous web and application servers with added SOAP functionality.

The book is organized in three parts: Distributed Application Protocols, Sample Application, and Web Services.

In Chapter 1, Distributed Application Protocols, we look at the major distributed application protocols and compare their pros and cons.

In Chapter 2, The Lingua Franca of the Web is SOAP, we review the SOAP specification in details and we take a closer look at the SOAP implementation that we will use in this book: Apache SOAP. In Chapter 3, Setting Up your SOAP Server, we get down to the details of downloading and configuring the necessary software to get your SOAP server up and running.

In Chapter 4, LeSavon.com, we move into the second part of the book with a discussion of the requirements for the sample application. Chapter 5, SOAP Server, is where we design and implement SOAP services. In Chapter 6, we write a client framework that will come handy when we wrap up the development of the sample application with its user interface. Chapter 7, Security and Personalization, discusses a possible integration strategy to an LDAP-based enterprise security system. Chapter 8, Caching, discusses how the addition of a rule-based cache system can tremendously improve the performance of our application. In Chapter 9, Performance, we analyze the performance of the sample application and validate the design and implementation choices that we made in the previous chapters. Chapter 10, Web Application, concludes the second part of the book with the addition of a Web-based Graphical User Interface (GUI) to our sample application.

In the third part of the book, we formally define Web services and discover that the sample application is indeed a Web service. Chapter 11, WSDL, introduces the reader to the Web Service Description Language (WSDL), a key technology that promotes the interoperability of software components over the Web. In Chapter 12, Universal Description, Discovery, and Integration (UDDI), we publish the sample application as a Web service and discuss how potential users can query the UDDI registry to discover our services.

Henry Bequet is Vice President of Internet Development with Sagent Technology, a business intelligence firm. Henry is a SUN-certified Java 2 programmer who specializes in developing scalable distributed Web applications using XML, SOAP, Java, and C++.