I'm hearing and reading more
and more about Inversion of Control (IoC) and dependency injection. The latter
is basically the idea of programming only to interfaces, and not knarling up
your code with factories to get concrete implementations of those, rather
letting something outside of an object "inject" the implementations,
prior to them being required. This injection can happen either through setter
methods, or constructors. So its inverting control, hence IoC. The container
controls which implementations an object gets, the object (class) is developed
against interfaces. Wiring the whole lot up is an exercise for the container,
based on some sort of (usually non-code based) configuration, like an XML file.
IoC containers that are on my radar include Spring (not just a container btw), PicoContainer and
HiveMind.
Its a bit weird at first, but
once you get used to it, the benefits become clear: code that is easier to
evolve, everything is pluggable, and unit testing is a doddle - you can isolate
units of code at a very granular level, stub everything else with test
implementations (like your junit TestCase can implement all of a test targets
dependencies and feed it exactly what it needs to prove some bit of
functionality).
2:56:04 PM 
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