Web Services-A Fit for EAI
A variation in the Integration Broker approach was evolved by plugging in pieces of software in different enterprise applications. The rationale behind attaching these software components (known as adapters) is to enable the enterprise applications to talk to a common, centralized system (known as an integration-bus) so that these applications can share information using this integration-bus. See Figure 3.
Figure 3—Integration-Bus Architecture
A typical business-service work flow (for example, an event-based work flow) can be designed and developed by using this approach.
As an example, Tibco products follow this approach. Tibco adapters sit on various applications (which are to be integrated) and the applications are integrated with an integration-bus (Tibco-Rv bus).
This approach requires the development of an adapter for each application to be integrated. Thus, it is a more useful approach where the number of entities to be integrated is fewer. In today's business, where each application needs to share information with an unpredictable number of entities residing at different locations, the Integration-bus-based EAI approach may not fit.
Java Connector Architecture
As the industry was progressing towards standardized ways to solve business problems, Sun Microsystems proposed Java Connector Architecture (JCA) as a Java-based, platform-independent solution to Enterprise Application Integration problems. JCA is an enhancement of the Integration Broker EAI approach and differs only in its J2EE implementation. JCA sits in a J2EE application server and interfaces among the various heterogeneous enterprise applications. This is a better approach than previous approaches because it allows the Internet users to talk to enterprise applications over J2EE architecture. See Figure 4.
John and Wilson Corporation went ahead with a pilot implementation using a JCA-based J2EE approach. This proved to be a standardized way to integrate in-house enterprise applications and also appeared promising. The integrated applications could be accessed over the Web. The JCA approach helped J&W significantly, thanks to its platform-independent attribute. J&W could establish interfaces among different applications running on disparate locations and platforms.
Service Oriented EAI
The IT industry continues to show its dynamics and now the concept of Service Oriented Application Integration has appeared. This is considered the biggest paradigm shift in IT, after the Internet revolution. The industry is recognizing the potential of Services on the Internet or intranet. The demand of this revolution is to broaden the enterprise perspective and aggregate or integrate any Service running on any platform on the Internet. Now the enterprises are not only worried about integrating their own applications sitting in their or their partner's premises, but also want to share information with other unknown applications running on the Web. To achieve this goal, standardized ways are required to integrate with applications, irrespective of where and how they are running.
The ultimate idea is to design a business work flow that solves the end-customer's problems. Integration of various services (exposed by enterprise applications) should be done in such a way that they can form a logical flow of a solution package. This concept is known as Work flow based Integration.
Giants of the IT industry (such as Microsoft, Sun Microsystems, IBM, and HP) realized the potential of Service Oriented Internet World and came up with specifications to materialize it. This set of specifications is called WEB SERVICES.
John and Wilson Corporation was among those organizations that could not resist the market trends in the Internet era. For the first time, J&W felt the immense pressure of customers as well as of suppliers/buyers to share its information with other applications running on the Web. Needless to say, that this was in addition to the integration among its internal or concerned (suppliers and buyers) applications. The applications running on the Web might be hosted on unknown platforms, implemented in unknown technology. Because of this, it was a great challenge for J&W. To adapt to this situation, J&W wants to opt for a technology that is based on the Internet standards and promises to establish the interfaces among various enterprise applications hosted anywhere (intranet or Internet) and implemented in any technology. The integration technology should be easier and cheaper to design, implement, and deploy. J&W finds Web Services a good fit for its requirements and goes ahead with the implementation at the intranet level with some access to its partners. The internal users, suppliers, and buyers are finding Web Services very useful and effective because of their loosely coupled and late binding attributes. Now the applications are exposed as Web Services and they are dynamically located and invoked using the organization's private UDDI registry. This is the way the applications and the Internet users share information with other applications. J&W is now ready for the future, which looks promising. The corporation is looking forward for Web Services standards to provide missing components so that this implementation can successfully be taken forward, live on the Web.
In this first part, we discussed the concepts of EAI and how its evolution has taken place. We concluded that EAI is moving towards Service Oriented Application Integration.
Based on this analysis, we will introduce Web Services and see their potential in the EAI sphere.
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About the Author
Manoj Seth is a senior software engineer at Hewlett-Packard, India. He is a Post Graduate from the Indian Institute of Information Technology, Bangalore.
Manoj has been involved in designing and developing J2EE-based solutions over various platforms in the domains of Financial/Banking and Middleware for more than two years. He has good exposure to Web Services and their emerging standards in development/deployment and management space. He can be contacted at firstname.lastname@example.org.
The author would like to acknowledge the contributions of Srinivas Varadarajan, Ashish Chitkara, Latha Bhashyam, Pankaj Kothari, Ravi Trivedi, Shyam Bijadi, and Jainendra Kumar at Hewlett-Packard, India for their insightful comments and reviews.
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