A quick
google search will reveal a raging debate on the merits of SOA. It has cooled down a bit from 2005 where every time I turned around, there was another session at Tech Ed on SOA. The talk about SOA has just started if its landscape is going to be anything like the adoption landscape for OOP. SOA has not lived up to it's hype yet, but to be fair, we have to give it another two decades.
We don't think about it much, but object-oriented programming began in the 1960's with the
Simula language. Smalltalk helped the movement, but C++ brought object-oriented development into the mainstream in the late '80s when the ANSI group was formed. From 1962 to 1989, OO was a lot of talk and theory with handfuls of folks implementing real systems using the concepts. When C++ hit, many more programmers came on board. Java furthered the adoption of object-oriented concepts, and .Net seems to have pulled the remaining part of the programming market into OO. When I think about how long it has taken for the average programmer to ackowledge OOP, I wonder if it will take that long for other paradigm shifts.
It remains to be seen if SOA really has the merits granted it by all the marketing hype or if it is just a new name for integration. We won't really know for at least another decade, I imagine. Folks have been integrating systems when necessary for years, so it remains to be seen if this new (everything is exposed as a service) strategy works.
I like the way
Jeremy Miller puts it: "The 'if you build it, they will come' approach doesn't work." I agree. As with any part in programming, building something with the wish that someone will use it someday doesn't work. If you are adding a service endpoint to a system out of necessity because someone else need to integrate NOW, then the business value is there, and it's the same kind of integration that has been going on for years. Some large companies need to integration now, and we see case studies galor:
google search.
What we won't find out until many moons from now is if these SOAs worked. Every project is declared a success immediately after completion, so we can't count on reported results right now. The true test is if these integrated enterprises are maintainable and cost-effective. Architects from big companies are saying "yes they are" right now, but no one thinks their child is ugly.