commons-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "James Carman" <ja...@carmanconsulting.com>
Subject RE: [collections] MultiMaps...
Date Fri, 13 May 2005 17:28:52 GMT
Upon further thought, why do we even have a class like MultiHashMap?
Couldn't we write a generic MultiMap implementation that wraps another map
and provides the "multiple" functionality?

public class MapUtils
{
  ...
  public static MultiMap multiMap( Map implementation );
  public static MultiMap multiMap( Map implementation, Factory
collectionFactory );
  ...
}




-----Original Message-----
From: James Carman [mailto:james@carmanconsulting.com] 
Sent: Friday, May 13, 2005 1:21 PM
To: 'Jakarta Commons Developers List'
Subject: [collections] MultiMaps...


I have a case in my application where I want to map one key to multiple
values.  However, I don't want the values to be stored as a List.  I would
rather have MultiHashMap store the values in a Set of some kind (HashSet
maybe).  It would be nice if I could tell MultiHashMap what kind of
collection to use to store the values.  Maybe we could parameterize the
constructor...

public MultiHashMap( Factory factory )
{
  
}

The factory would be used to create a collection instance each time one is
needed for a new key in the map.  Maybe this is overkill and we could just
give it a Class instance and it can call newInstance() on that.  Anyway,
that would allow MultiHashMap to return any kind of collection, not just
Lists.  Of course, I could just create a new Set using the returned List,
but that's a lot of objects to create.  What do you guys think?



---------------------------------------------------------------------
To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: commons-dev-help@jakarta.apache.org



---------------------------------------------------------------------
To unsubscribe, e-mail: commons-dev-unsubscribe@jakarta.apache.org
For additional commands, e-mail: commons-dev-help@jakarta.apache.org


Mime
View raw message