Design Pattern for implicit grouping

Hi,

In the context of simple OOP (C#):

Given a collection of elements, I need an efficient way to tag each element
as belonging to a group.

I cannot explicitelly bag all these elements into a separate list (use
explicit grouping):
I need to keep them independent for most observers except those specifically
interested in their group structure.

Groups can be nested (here lies the complexity) so each observer must be
efficiently able to get the outmost group of each elements as well as the
entire group hierarchy.

I must be able to tie items (element or group) to form a new group; and to
untie a group at any nesting level.

I know this is not a difficult, but I wanted to know if there any existing
pattern for it.


P.S: Of course I can use explicit grouping and use something else to let
most of the system see it as a lineal collection... but unfortunately I
can't do that at this point becasuse of the involved changes.

TIA

Fernando Cacciola
SciSoft

You can declare group manager classes for each of the groupings
you need. Whenever a user is assigned to the linear list,
add it to the corresponding group manager classes.

If a user is removed from the linear list, remove it from all group
managers.

The following article might help:
http://www.eventhelix.com/RealtimeMa...ignPattern.htm

Deepa
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http://www.EventHelix.com/EventStudio
EventStudio 2.5 - Automate sequence diagram generation