Chapter Two. Information-Oriented Application Integration

In this chapter we'll focus on the notion of moving information between two or more systems. This is the primary function of application integration. Although this seems to be a straightforward theory, you may want to watch out for some new concepts here including transformation, routing, and data analysis. Those topics will appear again later in the book.

Most application integration projects will leverage Information-Oriented Application Integration (IOAI). Indeed, IOAI is the ground floor of application integration, providing a simple mechanism to exchange information between two or more systems. This does not mean, as we covered in Chapter 1, that you can't mix IOAI with the other approaches to application integration, including service, portal, and business process integration. In fact, most application integration problem domains will eventually leverage all types. As we'll cover in later chapters, Service-, Portal-, and Business Process-Oriented Application Integrations are more invasive and thus more expensive, but in some cases, they are more valuable to the business as well.

Getting that out of the way, IOAI allows information to move between source and target systems. The data could come from a database, an API (e.g., SAP's BAPI), or perhaps an imbedded device. What's important to understand is that we're dealing with simple information, and not with processes or application services. The information-oriented approach to application integration professes that integration occurs between the systems by exchanging simple information (see Figure 2.1). We've been doing application integration this way for more than 30 years.

Figure 2.1. When using IOAI we are only moving information between the source and target systems; we are not addressing the notion of encapsulated processes or application services. However, that does not mean that IOAI is the only way to address application integration in this domain.

graphics/02fig01.gif

IOAI offers certain advantages.

  • First, we're dealing with simple information, so we usually don't have to change source and target systems. Most applications, certainly databases, already know how to produce and consume simple information.

  • Second, we don't need to manage complex issues such as state, logic, and sequence because there is no notion of behavior.

  • Finally, this approach is easy to understand and in wide use.

In many cases, the information-oriented approach is the correct solution. Using service or business process integration to integrate systems is contraindicated for many problem domains when looking at the business problems they are trying to solve. In fact, you'll find that service and business process integration approaches to application integration are overapplied.

Accessing information within databases and applications is a relatively easy task, accomplished with few if any significant changes to the application logic or database structure. This is a tremendous asset because altering applications is not possible in many problem domains, such as supply chains, where you are likely dealing with systems that are beyond your direct control.

However, the straightforward appearance of IOAI should not create the impression that it is simple. It is not. Migrating data from one system to another sounds straightforward and reasonable enough, but in order for IOAI to actually work, architects and developers need to understand all integrated systems in detail. We'll cover how to do this later in the chapter.

Application semantics make this problem even more complex. Typically, application semantics in one system are not compatible with other systems the semantics are so different that the two systems just can't understand each other. For example, sales accounting practices might be different, as well as invoice numbers and customer sales data. Thus, IOAI is not just about moving information between data stores, but also managing the differences in schema and content.



Next Generation Application Integration(c) From Simple Information to Web Services
Next Generation Application Integration: From Simple Information to Web Services
ISBN: 0201844567
EAN: 2147483647
Year: 2005
Pages: 220

flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net