Collections need: Array Map?

[Paul Johnson]

I have agents who wander around, encounter things, and make a note of 
the source of the "thing" and they create a "record" object to summarize 
what they found.  WHen they come to the thing again, they update the record.

I'm keeping the records in a map, using a string from the thing as the key.

Now the question my colleague asks is, "can you give me the 3 most 
recently altered (created/updated) records."

I've stared at this a long time and all of the scenarios I dream up seem 
horribly cloddish.  For example, create a new Swarm List to hold keys 
for the most recently encountered things (records). When you meet/update 
a record, search to see if the List contains that key already. If so 
remove it, and addFirst that record's key.  If the List does not yet 
have that key, then remove the Last item (assuming there are 3 or more) 
and then addFirst the new key. Blah.

So, before I go and do such a cloddish thing, I am asking if there is a 
more elegant approach, because there usually is.

--
Paul E. Johnson                       email: address@hidden
Dept. of Political Science            http://lark.cc.ku.edu/~pauljohn
University of Kansas                  Office: (785) 864-9086
Lawrence, Kansas 66045                FAX: (785) 864-5700


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