Re: factory objects (idle thoughts)
On Sun, 13 Sep 2009, Mike Schilling wrote:
Tom Anderson wrote:
However, the solution isn't necessarily a real constructor call. In
fact, i think it can't be - if you construct a concrete root factory,
then you're implicitly fixing the behaviour of the root factory's
factory methods, and so the factory methods of any factories created by
those, etc.
The root factory's behavior could be heavily influenced by configuration
parameters, the environment, the hardware resources available, etc.
The argument you're msking is analogous to saying that a computer's
behavior isn't flexible because it always searches for the disk boot
block at the same location.
If the disk can't be written to (in the way that classes can't be altered
at runtime, absent a debugger), then i think that analogy is moderately
sound. Yes, the root factory could have complex behaviour (as i said in my
post, in fact), but ultimately it is limited to the options available when
it was written. If you get the root factory by dynamic loading, then
it's an extension point which admits infinite possibilities.
Of course, not all problems need infinite possibilities to solve, and a
hardwired flexible root factory may be a better choice than a dynamically
loaded one, particularly if you don't have a dependency injection
framework to make that easy for you.
tom
--
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