Moving from Information-Oriented to Service-Oriented Application Integration

A clear trend is the movement away from information-oriented to service-based integration. Information-oriented integration provides an inexpensive mechanism to integrate applications because, in most instances, there is no need to change the applications.

While information-oriented integration provides a functional solution for many application integration problem domains, it is the integration of both application services and application methods that generally provides more value in the long run. That is the underlying theme of this book.

For example, a trading community looking to automate the processing of ordering raw materials may find that simply sharing information (order goes out, and confirmation comes in) is just fine to solve their integration problem. However, in another trading community, there may be a need to access remote services, such as the calculation of duty for intercountry trades. Again, you have to leverage the right approach for the business problem you are looking to solve.

Service-based application integration is not a new approach. We've been looking for mechanisms to bind applications together at the service level for years, including frameworks, transactions, and distributed objects all in wide use today. However, the new notion of Web services, such as Microsoft's .NET strategy, is picking up steam as we attempt to identify a new mechanism that's better able to leverage the power of the Internet to provide access to remote application services through a well-defined interface and directory service: Universal Description, Discovery and Integration (UDDI).

The uses for this type of integration are endless, including the creation of composite applications, or applications that aggregate the processes and information of many applications. For example, using this paradigm, application developers simply need to create the interface and add the application services by binding the interface to as many Internet-connected application services as are required.

The downside, at least with service-based integration, is that this makes it necessary to change the source and target applications or, worse in a number of instances, to create a new application (a composite application). This has the effect of adding cost to the application integration project and is the reason many choose to stay at the information level.

Still, the upside of this approach is that it is consistent with the "baby step" approach most enterprises find comfortable when implementing solutions to integration problems. Service-based solutions tend to be created in a series of small, lower-risk steps. This type of implementation can be successful from the department to the enterprise to the trading community, but never the other way around from the trading community to the department.