Chapter 11
Dealing with Adapters
In This Chapter
Discovering the true nature of adapting
Getting to know the ties that bind
Deciphering adapters
Building adapters
Adapters make SOA possible. No adapters, no SOA — it’s as simple as that. More than anything else, SOA enables the reuse of the business applications that you already have. To do that, you need to add interfaces to these applications that allow you to directly invoke — from any other program, mind you — the functions these applications contain. The SOA adapters provide these interfaces.
The easiest way to understand adapters is to realize that all software of any kind has an interface of one kind or another. It doesn’t matter what the software does. And not just business software, but any kind of software — word processors, games, PC calculators, Web sites, and programs run by NASA to calculate the correct trajectory for a space probe as it passes Jupiter on its way to Saturn — they all have interfaces. Gobs of them.
All software does something, but it does what it does only when some user (or possibly another program) tells it to. The user or the other program gives the software the command through its interface. And the software presents information back to the user or a computer program also through its interface. That, in fact, is precisely what an interface is — the connection point that a program has with a user or some other program. For example, a person might connect with a software application through a multicolored ...
