- What Is a Web Service?
- Crystal Ball Readings
- The ABCs of Web Services
- How to Use a Web Service
Crystal Ball Readings
Web services are rapidly changing, and represent different things to different people. Because of this, it is important to give you an idea of what to expect in the future in order to place what you are learning in proper perspective. The goal is to show the probable direction of Web services. Of course, by the time you read this section, some of these predictions will have been realized or will no longer be possible, which means that you should take these predictions with a grain of salt.
So what can we expect for the future from Web services?
The year 2002 will be marked with as many failures as successes with regard to Web services. The failures will result from trying to replace more traditional business models with Web services. Successful Web service implementations will be systems that start small or integrate Web services into existing business practices. This means that most failures will be due to projects pushing the Web services paradigm too fast and too hard.
Web service implementation will become stabilized and by mid-2002 most J2EE servers will implement an easy front end to make using Web services more transparent.
Web service tools will be divided primarily between Microsoft's .NET Framework and Java J2EE implementations. Since Web services are product independent, this doesn't pose a problem. Developers will chose to build Web services using the tool that best matches their business needs.
Web service design structure will become more stable. By the end of 2002, the influence of successes and failures will establish practical business design guidelines for building successful Web services.
The initial market for Web services in 2002/2003 will be smaller than what the 2001 hype portrays. New technologies very rarely live up to the hype, and the slow economic realities of 2001 will only slow Web services.
Ironically, Web services will be most effectively used internally, providing a place to centralize and reuse business logic across many different Web applications for larger companies and state organizations. For some Java shops, this will be a method to avoid using EJBs. Enterprise JavaBeans are distributed Java objects (they are not JavaBeans, which are basically standalone Java objects). Most shops will tie EJBs and Web services closely together for their business. This in effect will create two different styles of Web service implementation for Java programmers: EJB-based Web services and JSP/Servlet/JavaBean-based Web services. The difference between the two styles will be a reflection of the framework being implemented by a project. Systems using J2EE systems will usually implement EJB-based Web services, while smaller projects based solely on JSP/servlets will use Web services based on JSP, servlet, and JavaBean technologies.
In 2003, Web services will begin to be included in Web application design. This means that Web services will be used not by early user pioneers, but by businesses.
The development of Web services can be highly automated and most Web service development will be through these automated tools. The first solid tools will be available in 2002. However, it won't be until 2004 that these tools will be fully mature and in widespread general use.
Many implementations of Web services will fail as programmers experiment with the boundaries of Web service design. This will be similar to the trend of implementing EJB designs when simpler designs would have been quicker, cheaper, and simpler to build.
Finally, expect that Web applications of the future will only use a handful of commercial Web services. The Web services market will be similar to the COM market for building Microsoft-based solutions. People will use public domain or commercial Web services to complement their applications for a few tasks, but the majority of programmers will build their own for specialized tasks.
These predictions are based on the authors' experiences with various technology implementations over the past 15 years. This isn't a scientific study of consumer need, but rather is based on similarities between Web services and other products.
All of this leads to the conclusion that, due to the slippery and constantly changing nature of Web services, the majority of programmers should not rush into using them. Instead, we suggest that you carefully and slowly enter into the Web services marketplace. Start with small implementations to gain experience. Once you've reached an understanding of Web services and the major tools have matured to the point at which they're acceptable for your business needs, jump in with both feet. Due to the small and distributed nature of a Web service, taking a slow and controlled approach is very practical.
This book has three chapters that pertain specifically to Web services:
This chapter provides an introduction to the various APIs that a Web service might use in its implementation.
Chapter 8, "Integrating JSP and Web Services," demonstrates how to implement Web services in a JSP-only environment. This book will not examine how to use Web services within a J2EE application server.
Chapter 14, "Building a Web Service," will cover the basics needed to get you to a point at which you can implement a Web service that others can access through an UDDI registry. Web services should be simple enough to build and use without much fuss.