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From: Lew <lewbloch@gmail.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: equals(), Sets, Maps, and degrees of equality
Date: Sun, 13 Nov 2011 21:18:13 -0800 (PST)
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Lew wrote:
> Sean Mitchell wrote:
>> Lew wrote:
>>=20
>>>>> consider a class Dog:
>>>>> public class Dog {
>>>>> =A0 String breed;
>>>>> =A0 String name;
>>>>> =A0 String age;
>>>>> }
>>>>> I may want to have a Set<Dog>, which holds only one Dog of each breed=
,
>>>
>>> This is terrible modeling.
>>=20
> > Really. Why?
>=20
> Because you want to use 'Dog' to model 'Breed', and they aren't the same =
thing at all.

Also, "age" is not purely an attribute of 'Dog', but of 'Dog' plus "now".  =
It makes no sense to store an age that will be obsolete the instant it's st=
ored.  Rather, store the birthday.

--=20
Lew