./java/extending-collections.txt

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05:03 < multi_io> hmm, a class with only private constructors is not only not 
                  instantiatable, it's also not extendable, right?
05:03 < ojacobson> multi_io: true
05:04 < ojacobson> Not quite non-instantiable, methods (even static ones) in 
                   the same class can create them.
05:04 < ojacobson> But close enough for gov't work.
05:04 < multi_io> I wanted to "add" my own utility methods to 
                  java.util.Collections by deriving myproject.Collections from 
                  it and adding the methods to that
05:05 < multi_io> it feels stupid to write a completely disjoint class 
                  MyCollections
05:05 < ojacobson> multi_io: what would you gain by inheriting from Collections?
05:06 < multi_io> ...and then always having to remember whether a given method 
                  is defined in java.util.Collections or myproject.MyCollections
05:06 < ojacobson> Anyways, Collections is not (afaik) final
05:06 < multi_io> ojacobson: as I say, I just want to "add" some methods to it 
                  that were "forgotten"
05:06 < ojacobson> You can derive from it, you just can't instantiate your 
                   derived class.
05:07 < ojacobson> ...wait, I might be lying furiously.
05:07 < multi_io> I can'T.
05:07 < multi_io> compiler complains b/c the construictor can't call super()
05:07 < ojacobson> right, because the default constructor would have to invoke 
                   the parent class's () constructor, even if you provide one.
05:08 < multi_io> well, this sucks
05:09 < ojacobson> In that you might have to remember what methods you 
                   implemented, yes
05:09 < ojacobson> I have to admit, I'm not seeing the huge burden
05:09 < r0bby> nice.
05:10 < multi_io> it appears I'm gathering a bunch of feature requests for Sun 
                  here
05:10 < multi_io> make for() able to use Iterators, make j.util.Collections's 
                  constructor protected
05:11 < ojacobson> I guarantee you both will be closed nearly immediately
05:11 < ojacobson> the former "duplicate" the latter "won't fix"


http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6588768
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