Change | XML, Web Services, and the Data Revolution


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	XML, Web Services, and the Data Revolution By Frank P. Coyle
	Table of Contents

	Chapter 8. Back to the Future

XML is a driver of change.

The overriding theme of this book has been change: change brought about by XML and its capacity to describe data not only in the conventional IT sense of the word, but in the more general sense that includes directives for action also known as "code." Yet XML is more than just a technology for delivering data or code as data; it is a part of a broader effort to build applications out of constituent parts rather than to construct hard-wired solutions.

SOAP is the product of XML and HTTP.

The Web itself ”a product of HTTP, HTML, and the browser ”is an example of this power of convergent assembly. SOAP is another example, itself a product of the Web (as transport) and XML (as data). What these technology combinations give us is a freewheeling Web space of loosely coupled asynchronous communicating servers that are finding their place amid existing object systems and legacy applications.

Convergence

The Web is fertile ground for convergence.

The computing world where we now find ourselves is an amalgam of players and technologies, all trying to find synergies through interconnection. As Figure 8.1 illustrates, the main pieces coming together include the loosely coupled Web riding on waves of SOAP and XML, more traditional tightly coupled object systems bound by their own transport protocols but able to support critical transactional capability, and the even more traditional legacy applications, many of them running on large mainframe environments. The irony here is that the central repository model made possible by the mainframe and once thought to have been made obsolete by client-server network computing is now experiencing a renewed interest due to several factors, including delivery of services to critical applications, high-bandwidth throughput, and more recently the need to manage collaborative P2P efforts over the loosely coupled Web.

Figure 8.1. The three major pieces of application space.

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The challenge is to bring tightly coupled and loosely coupled systems together.

The challenge for the software industry is to work out the details of the interplay between tightly coupled object systems and the loosely coupled Web. As we saw in Chapter 5, the force bringing these two entities together is the need to add transaction and messaging to the Web. The result (as we've seen in Chapter 6) is Java 2 Enterprise Edition (J2EE) and .NET. However, there are other kinds of interaction that play a role in the future shape of the new Web. These include

Integrating legacy mainframe applications between tightly coupled object frameworks and the Web
Identifying clients plugging in from the loose space of the Web to traditional tightly coupled networks
Understanding how the loose space of the Web is opening up new ways of P2P and collaborative interaction and how these new models of interaction fit with the more conventional computing models

Thus we've now got three very different subsystems looking to find each other and interconnect in new ways to arrive at new synergies. So while it's unwise to try to predict, it is at least reasonable to expect the immediate future will be based on the interactions between the three forces of mainframe legacy applications, tightly coupled client server systems, and the new more open space of the Web.

In the following sections we explore each of these interactions to get a glimpse of what may be in store in the near future.


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