Xavier Hanin wrote:
My idea was to distinguish constructors (I defined two actually: one
with no
arguments, and one with all options as parameter) from factory method
which
actually process the argument to find what values should be for
options (the
settings is not part of the attributes of DeliverOptions, it's only
used to
give default values to the actual attributes). Another thing is that
factory
methods have the advantage to be more flexible (as explained in the
excellent "Effective Java Programming" you've certainly read). But in
this
case I don't see how it could really help, so if several people prefer
constructor, I'll go with it, no problem.
My main concern for this type of thing is:
1) you introduce dependencies into another component (IvySettings for
instance)
2) introducing this method, basically means that your class is final and
inheriting it is not an option at all.
Overall in this specific case dependencies and constraints about the
model are introduced while you get no benefit in return.
Indeed a DeliverOptions is actually created when you deliver...which
means you do it only once in Ivy class.
I'm not sure to see what you mean. If I provide an IvySettings object,
I can
have good default values for my attributes. Otherwise I can't, for the
cache
for example. So does it mean I should avoid the empty constructor to
be sure
a DeliverOptions won't ever be badly set?
As long as the contract is clearly established, to me that's pretty much
fine...
After all that's what the bean and dependency injection is about
And I'm no real fan to full constructor injection because this is
unreadable and people tend to stack all possible properties which
becomes a nightmare when most of them are the same type, it's unreadable
and error prone. In general arguments in the constructors are the
'critically needed' one and maybe another one or 2 constructors with 1
or 2 additional arguments as a helper.
The problem you're having with the cache is because the cache is not
fully abstracted (or at the very least the 'repository) all while it
should be totally transparent to most objects...well that would be a
pain to fix all that but there's no reason to actually have the logic
deported everywhere and force you to pass the cache reference everywhere.
-- stephane
