gistfile1.txt

I started working on an EmailAddressPartitioner that sorts user@example.com as com.example@user, 
but I'm confused what the role of Token objects is supposed to be. The Token classes have 
essentially no javadoc and classes that use them seem to assume you know exactly how Tokens fit 
into everything.  Should the token be (essentially) the decorated key?  What's the meaning of the 
default token?  Existing implementations use a random value if the config file doesn't specify 
anything, so I assume the default token doesn't have to correspond to an actual key.

It looks like the midpoint method does the important work, but it's not clear exactly what semantics 
are desired.  If I'm partitioning keys that map to Strings, is there a reason to not use the 
OrderPreservingPartitioner's implementation?  That is, is there any semantic meaning to the result 
of midpoint(), or is it data agnostic?