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Java Web Services by Tyler Jewell, David A Chappell

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Web Services Adoption Factors

Web services are new technologies and require a paradigm shift. The adoption of web services is directly impacted by the adoption of the paradigm of web services development.

A paradigm shift can happen quickly in a large wave, when suddenly the whole world is doing something differently, and no one notices how and when it happened until after the fact. An example of such a shift is the World Wide Web phenomenon that began around 1995. The combination of HTML, HTTP, and the CGI programming model is not the most efficient way to accomplish the services offered by these technologies, yet the CGI model gained widespread grassroots acceptance because it was simple and easy to adopt.

The acceptance of CGI started the wave. To become a lasting paradigm shift, the model of web-based business needed broader acceptance among corporate IT and industry leaders. This acceptance was encouraged by continuing standards development within W3C and IETF and through continuing technology innovations such as ISAPI, NSAPI, Java Servlets, and application servers. Eventually, high-level architectures and infrastructures such as .NET and J2EE were created to hold everything together.

Unlike the initial adoption of the Web, which was driven by grass-roots demand, the adoption of web services will be driven downward by corporations. It’s still a paradigm shift, but it’s likely to move more slowly. The adoption of the fax machine provides a good analogy. Because fax machines were initially large expensive devices, they were adopted first by large businesses as a way to communicate between their offices. As more companies bought fax machines, they became important for business-to-business communications. Today, fax machines are nearly ubiquitous—you can fax in your pizza order. We expect to see the same trend in web services. They will be used first for internal business communications before they become part of everyday life. In all cases, though—the rapid adoption of the Web, the slower adoption of the fax machine, and the current adoption of web services—the same factor has enabled the paradigm shift. That factor is a standards communications mechanism. Whether the standard be the phone line and FAX protocols, the TCP/IP stack and HTTP (together with the phone line and modem protocols), or the web service protocols, standards have been, and continue to be, the key factor in enabling the acceptance of new technologies.

Industry Drivers

Many tangible drivers make web services technology attractive, both from a business and a technical perspective. Classic Enterprise Application Integration (EAI) problems require applications to integrate and interoperate. Even within a particular business unit, there exist islands of IT infrastructure. For example, a Customer Relationship Management (CRM) system may have no knowledge of how to communicate with anything outside of its own application suite. It may need to communicate with a third-party Sales Order system so it can know about new customers as soon as they place their first order.

Corporate acquisitions and mergers are also an issue. Entire parallel business application infrastructures have to be synchronized or merged. Business partners such as suppliers and buyers need to collaborate across corporate boundaries.

These EAI and B2B problems exist in abundance and are increasing exponentially. Every new deployed system becomes a legacy system, and any future integration with that system is an EAI or B2B problem. As the growth of integration problems and projects accelerates over the next couple of years, the standards-based approach that web services offer makes adopting web services technology an attractive option for companies that need to cost-effectively accomplish seamless system integration.

Lessons Learned from Recent History

Some industry analysts claim that the web service model is causing a paradigm shift that will change the way distributed computing is done forever. Others say that this model is just a fad that will go away soon. Currently, web services is still very much in the hype phase. Drawing parallels to other new technologies can teach us important lessons.

Other distributed-computing models have had an opportunity to garner universal acceptance and adoption, yet they have not. While these models offer great technical advantages for solving real problems, none have achieved the massive widespread adoption that their proponents had hoped for. This is largely due to their proprietary nature and the inevitable vendor lock-in. Though COM/DCOM had a widespread following, it could not permeate an enterprise because it was limited to Microsoft platforms. CORBA was controlled by the OMG, a neutral standards body. However, software availability was a problem. There were really only two robust vendor implementations: Iona and Visigenic.

Forcing middleware infrastructure down the throats of other departments and business partners is not easy. Both CORBA and DCOM required that a piece of the vendor-supplied middleware be installed at every node of the system. You can’t always force a business partner to install a piece of your software at their site for them to be able to participate in business transactions with your systems. Even within the four walls of an organization, agreeing upon and rolling out an enterprise-wide middleware solution is a huge, concerted effort. CORBA implementations eventually achieved cross-vendor interoperability, but by then it was too late; the wave had already passed.

Crossing corporate boundaries in a secure, reliable fashion is key. If you go back only as far as 1996 to 1997, you would have seen every trade magazine talking about a world of distributed CORBA objects happily floating around on the Internet, discovering one another dynamically and communicating through firewalls. Standards were proposed for firewall communications, and IIOP was going to be adopted by all major firewall vendors as a recognizable protocol. It just never happened—partly due to the aforementioned adoption problems and partly due to widespread adoption and general acceptance of HTTP as a firewall-friendly protocol.

Why Web Services, and Why Now?

What is so different about web services, and why are they poised for success, whereas other preceding technologies have failed to achieve widespread adoption? The answer lies in the challenge that every organization faces today: to create a homogeneous environment while still leveraging its core abilities and existing applications. IT needs a simple, platform-neutral way of communicating between applications.

For starters, XML is ideal for representing data. IT developers have had exposure to XML for a few years and they understand what it’s good for. Even though the average IT developer hasn’t yet become a walking XML parser, by now most developers understand the concepts behind XML and how it can be used.

Also, the base technologies of SOAP, WSDL, and UDDI are not themselves very exciting; they are just new dressings for the same old distributed-computing model. What draws people to them is the promise of what they enable. Finally, we have a platform-neutral communication protocol that provides interoperability and platform independence. A bidirectional conversation may occur between a Biztalk server and a set of hand-rolled Perl scripts. The Perl scripts may be simultaneously involved in a conversation with a set of applications held together by a J2EE-based application server or a message-oriented middleware (MOM) infrastructure. The minimum requirement is that each participant in the multiparty collaboration knows how to construct and deconstruct SOAP messages and how to send and receive HTTP transmissions.

The heavy involvement of the Microsoft camp and the J2EE camp in web services is good for everyone. It’s advantage is not about .NET versus J2EE or .NET versus SunONE; it’s about the fact that you no longer have to let that debate or choice get in the way of achieving interoperability across the enterprise. The programming languages and associated infrastructure of each respective camp will continue to coexist and will remain “camps” for a long time.

Low barrier to entry means grass-roots adoption

The widespread adoption of web services can be predicted by drawing parallels to the CGI phenomenon discussed earlier.

Similar conditions exist today. The straightforward approach that SOAP takes—XML messages sent over HTTP—means that anyone can grab Apache SOAP and start exchanging data with the application owned by the guy down the hall. There isn’t any overly complex, mysterious alchemy involving a strategic architecture group that takes two years to figure out. A corporate-wide infrastructure adoption shift doesn’t need to occur for a company to start working and benefiting from web services; companies can be selective about how and where they adopt these technologies to get the best return on their investment.

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