thanks everybody

[Jean Lutrin]

Hi everybody,

thanks a lot for all the answers, it helped me a lot.

A Set is indeed a more correct abstraction than a Map (even
if, say, an HashSet is implemented using an HashMap).

What I didn't realize was that .equals() and .hashcode() were
supposed to be consistent (I say "supposed" because there's no
doubt that some programmers forget to comply with this rule).

For whatever reason I was thinking that the hash value was
generated from the reference of the object, which was of
course completely false.

As a funny side note, it means the way I solved my problem
while thinking I was wrong is actually correct

Thanks a lot for all your answers,

Jean

 

[Tim Ward]

What I didn't realize was that .equals() and .hashcode() were
supposed to be consistent (I say "supposed" because there's no
doubt that some programmers forget to comply with this rule).

They are supposed to be consistent. Some programmers don't realise that -
programmers who fail to comply with the rule are, I would guess, mostly
programmers who've never heard of the rule rather than programmers who've
forgotten to do it.

You can get very interesting results if you fail to comply with this rule -
you quite likely get away with it for a while, but weeks or months later,
when you've forgotten how the class in question was implemented, you start
using it in a different way and it all goes pear shaped.

 

[Roedy Green]

goes pear shaped.

I know of only one other person who uses that expression. He lives in
Binegar near Bath in Somerset England. Is that a regionalism?

 

[Daniel Dyer]

I know of only one other person who uses that expression. He lives in
Binegar near Bath in Somerset England. Is that a regionalism?

Maybe it's a British thing. It's quite a common expression over here.

Dan.

 

[Tim Ward]

I know of only one other person who uses that expression. He lives in
Binegar near Bath in Somerset England. Is that a regionalism?

Don't think so, think it's in fairly common usage across the UK. (Although I
did grow up in Bristol, 12 miles from Bath.)