SOA Day 3 - We have to shift our mindset if we want successful SOA

Day 1 - Connections = Cost to Connections = Value
Day 2 - Function Oriented to Process Oriented

Continuing the series of mental shifts today we will cover how we build things and the development approach needed.

From Build to last to Build for change. This is another one that people struggle to get out of. It is tempting to think that we are building a system or component that will last forever, that it will not need change. To support this we tend to build in "what if's" and architect a solution until we are blue. What we really need to do though is focus on building in abstraction layers and flexibility, accepting that the system and requirements are going to change.

An interesting item in architecture is that those requirements that have the most churn about them are the ones that need the most flexible designs. A good portion of this flexibility can (and should) be built in through abstraction. If it doesn't matter what whatchamadigger you have behind the library because the library is generic then it gives you the ability to change along the way. This goes for both custom/internal code as well as external components.

A good example of this work the various MOM efforts everyone seems to be working on. Currently they are working on building abstraction libraries for several potential message queue systems. Websphere MQ, JBoss Messaging and SeeBeyond are all potential solutions and rather than building to one specific solution a better approach is to build interfaces that abstract out which mechanism is used behind the scenes. In this manner the teams who are doing the integration don't need to worry about the plumbing and can focus on the application logic needed to differentiate applications instead of the things that should "just work". Another major benefit of this approach is that it frees teams to move to new and different technologies with minimal rework and this is where real negotiation power with vendors and true flexibility in technology by avoiding lock in can be found.