Re: hashCode

From:
Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 30 Aug 2012 21:43:07 -0400
Message-ID:
<k1p4rh$im0$1@dont-email.me>
On 8/30/2012 6:52 PM, Daniele Futtorovic wrote:

On 29/08/2012 20:49, Eric Sosman allegedly wrote:

On 8/29/2012 2:06 PM, Daniel Pitts wrote:

On 8/28/12 5:02 PM, markspace wrote:

On 8/28/2012 4:33 PM, Daniel Pitts wrote:

interface Hasher<Type> {
     int hash(Type t);


The difficulty is that an external Hasher would have no access to
private fields (...)


This.


     ?

    package deal;
    public class ToBeHashed {
        private int noGettersForMeThanks;
        ...
    }

    package express;
    Hasher<ToBeHashed> hasher = new Hasher<ToBeHashed>() {
        public int hashCode(ToBeHashed obj) {
            // How do you obtain the value of
            // obj.noGettersForMeThanks
            // if that would be useful?
        }
        ...
    }

As an example of why a hasher might want access to a strictly-private
field, I offered String: How could a Hasher<String> (outside String
itself) use String's private `hash' element? (And before you say
"Give String a getHash() method," ponder what hashCode() does.)

--
Eric Sosman
esosman@ieee-dot-org.invalid

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