HInterface

An HInterface object represents actual human interface devices connected to the hardware and visible to the server.  These are managed by the server and are only of interest to Abstraction writers for the most part.  When devices are connected they are given HInterface objects in order to interface with Abstraction objects.  Abstraction objects decide whether to attach themselves to specific HInterface objects of specific types.  When the interface device produces input the corresponding HInterface object takes that input and passes it along to any Abstractions that are attached to it in the form of a device part and value.