A Changeset and its subclasses will encapsulate the idea of a set of changes. A set of changes could be broken down into various categories such as a specific revision, a list of directories, a list of files, a list of blocks of code, and finally a line of code.

A ChangesetFactory is supposed to return a change set based on the type of change set requested. To get the requested change set, one needs to know the type of revision control system (SVN, CVS, other, etc.) and/or the data required to connect to it. So there obviously need a link between RCS and ChangesetFactory/Changeset. The question is how? What is the proper/best way to link them together? One way is to pass in an RCS object to the ChangesetFactory which would then pass that object to the appropriate Changeset subclass. I don't like that solution but it's the simplest.