Review Request CR#7118743 : Alternative Hashing for String with Hash-based Maps (original) (raw)

Mike Skells mike.skells at talk21.com
Wed May 23 07:38:39 UTC 2012

Hi Mike,

I have a query, why is this implementation limitted to String? Is this by intent?

in HashMap the patch for hash calculation is   290     final int hash(Object k) {  291         int h = hashMask;  292         if ((0 != h) && (k instanceof String)) {  293             return h ^ ((String)k).hash32(); .... whereas I would have thought that it should be   290     final int hash(Object k) {  291         int h = hashMask;  292         if ((0 != h) && (k instanceof Hash32)) {  293             return h ^ ((Hash32)k).hash32(); ....

As a more flexible improvement could you supply a HashCode and Equals delegate, and then the user can supply either a custom delegate, suitable for that application (e.g.one that iterates through array content, or any other application data structure that needs to be handled differently like c# uses http://msdn.microsoft.com/en-us/library/system.collections.iequalitycomparer )

Regards

Mike

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