The Multiton Design Pattern   Many people have independely
discovered a new design pattern, the “Multiton”, which, like the
“Singleton” is an initialization pattern in the style of the
Design Patterns book. Like the Singleton, the Multiton provides
a method that controls the construction of a class: instead of
maintaining a single copy of an object in an address space, the
Multiton maintains a Dictionary that maps keys to unique
objects.  The Multiton pattern can be used in systems that store
persistent data in a back-end store, such as a relational
databases. The Multiton pattern can be used to maintain a set of
objects are mapped to objects (rows) in a persistent store: it
applies obviously to object-relational mapping systems, and is
also useful in asynchronous RIA’s, which need to keep track of
user interface elements that are interested in information from
the server.  An alternate use case of Mulitons, seen in the
“Multicore” version of the PureMVC framework, is the extension
of the Singleton pattern to