Yes, I believe you would have a new tagging interface called BandedSymmetric. Implementing both interfaces would probably open things to many errors...
2011/7/2 Sébastien Brisard <sebastien.bris...@m4x.org> > But if you have a method taking as an input a matrix which MUST be both > symmetric and banded, you are bound to define a new interface. > Am I wrong? > Maybe the alternative you are thinking of is testing "instanceof > SymmetricMatrix" and "instanceof BandedMatrix" in the implementation of the > method, instead of specifying the required matrix in the declaration of the > method? > > Le 02/07/11 21:18, Greg Sterijevski a écrit : > >> Not a stupid concern in my book. However there is a synchronization >> mechanism in place. We are taking part in it right now. Whether the new >> matrix implements both SymmetricMatrix and BandedMatrix or is a new >> tagging >> interface (SymmetricBanded) would determined in the list, after a bit of >> back and forth. >> >> 2011/7/2 Sébastien >> Brisard<sebastien.brisard@m4x.**org<sebastien.bris...@m4x.org> >> > >> >> Marker interface seems to be a very elegant solution. I am just wondering >>> about a potential issue. Let us assume we defined two interfaces, say >>> SymmetricMatrix, and BandedMatrix. User A writes a matrix class which >>> implements both interfaces. Meanwhile, user B implements an algorithm >>> which >>> requires a symmetric, banded matrix. Presummably, user B will define a >>> new >>> marker interface, which extends both SymmetricMatrix and BandedMatrix. So >>> we >>> have on the one hand >>> >>> class UserAMatrix implements SymmetricMatrix, BandedMatrix; >>> >>> and >>> >>> UserBAlgorithm.operate(****BandedSymmetricMatrix). >>> >>> One day, user A hears of the work of user B. The matrix he has >>> implemented >>> has just the required features (symmetric *and* banded). But it does not >>> implement BandedSymmetricMatrix, so he cannot apply >>> UserBAlgorithm.operate >>> to an instance of UserAMatrix. There is always the possibility of >>> creating a >>> new class which extends UserAMatrix and implements BandedSymmetricMatrix, >>> but that would obfuscate the hierarchy tree. Is this a problem? Is that a >>> stupid remark? >>> >>> Sebastien >>> >>> >>> >>> ------------------------------****----------------------------** >>> --**--------- >>> To unsubscribe, e-mail: >>> dev-unsubscribe@commons.**apac**he.org<http://apache.org> >>> <dev-unsubscribe@**commons.apache.org<dev-unsubscr...@commons.apache.org> >>> > >>> >>> For additional commands, e-mail: dev-h...@commons.apache.org >>> >>> >>> > > ------------------------------**------------------------------**--------- > To unsubscribe, e-mail: > dev-unsubscribe@commons.**apache.org<dev-unsubscr...@commons.apache.org> > For additional commands, e-mail: dev-h...@commons.apache.org > >
