Metacat

This idea should be generalized to include a shared pool of connections for most
of the important objects like Conneciton, DBReader, DBTransform, and DBQuery.
These objects will need to be thread safe. When a client makes a request, one
of the objects is assigned to that client for the duration of the request, and
then returned to the pool when the request completes. In this way, we avoid the
overhead of creating new objects for every request, but we can still service
multiple requests at a time.

assigned to Jivka Bojilova

DONE
Implemented Pool of Connections only.
DBQuery, DBReader and DBTransform are created on every request.
MetaCatUtil class contains the implementation of the Pool stored in Hashtable.
Every object that needs a Connection for its work gets one from the Pool and
returns it in the Pool when it is done. Initial number of Connections is created
at first, but open a number of new Connections (no more than the maximum
allowed) when Connection object is requested and all Connections in the Pool are
busy at that moment. Before the Connection to be given to the caller check for
existence (implicitly closed) or any problems with the Connection (by quick
setAutoCommit(true) call) and if any it is replaced with new Connection.

Original Bugzilla ID was 23