The Events2HVAC system uses a provider model design to allow the program to install and use a common, pre-defined interface for Google Calendar server versions. The model allows the interface to be loaded at runtime and easily replaced or modified without recompiling the main Events2HVAC application.
The Google Calendar event provider was specifically designed to interface to the Google Calendar API for room calendars and Google Admin SDK and Google Data API for room resources.
The diagram below illustrates how the components of Events2HVAC interact with other systems. The Google Calendar event provider pulls schedules through the Google Calendar API (left), while various device interfaces can be installed to send commands to different HVAC systems (right).
Figure 1- Google API Interface to Events2HVAC