Binary Conversion functions

[Doug Lea]

Are there existing interfaces or usage tricks for existing
interfaces for what I had placeholded in ConcurrentHashMap
for two non-primitive args ->  primitive result:

     /** Interface describing a function mapping two arguments to a double */
     public interface ObjectByObjectToDouble<A,B> { double apply(A a, B b); }
     /** Interface describing a function mapping two arguments to a long */
     public interface ObjectByObjectToLong<A,B> { long apply(A a, B b); }
     /** Interface describing a function mapping two arguments to an int */
     public interface ObjectByObjectToInt<A,B> {int apply(A a, B b); }

If not, and no one thinks they belong in j.u.functions,
I'll just keep them as local interfaces in CHM.

-Doug