android_procedure.txt

Formats:
	timestamp		YYYY-MM-DD HH:mm:ss (24 hour)

Raw Data: (list of usage information for each application on the device during the requested interval)
  Application ID - Internal name of the application.
  Start Time - The time at the start of the 5 second interval in milliseconds.
  End Time - The time at the end of the 5 second interval in milliseconds.
  Total Time - The absolute total time that the application has been in the foreground in seconds.
  Last Time - The time that the applicaiton was last opened (units not known).
  Launch Count - The number of times the application was launched within the interval.
  
Procedure:
  Every 5 seconds, we obtain a list of application activity within the preceeding interval.
  We maintain two copies of this list: one for the current interval and one for the previous.
  
  We maintain two buffers:
    - The Open Buffer is a list of applications that are currently in the foreground (should only have 1 entry at a time).
    - The Output Buffer is a list of application sessions that are waiting to be sent to the server.

  Each time we collect application activity,
  
  If the Total Time of the current interval is not the same as the previous,
    and the application is not in the Open Buffer, we add it to the buffer.
  The Open Buffer record contains the App ID, Start Time, End Time, Total Time, and Last Time of the current interval.
  
  For each application in the Open Buffer, we compare the current and previous Total Time.
  If the times are not the same, then the application was in the foreground during the interval, and we update the End Time and Total Time records.
  
  When the application is closed, we move the record from the Open Buffer to the Output Buffer.
  Before adding to the Output Buffer, all timestamps are converted from milliseconds into seconds, and from 64-bit integers to 32-bit integers.
  
  Once per day, or when the Output Buffer is full, we send the Output Buffer to the server and clear the Output Buffer.
  
Collected Data:
  Each entry in the database contains a single instance of application foreground usage.
    Application ID - the internal name of the application.
    Start Time - the timestamp at which the session started (accurate to 5 seconds).
    End Time - the timestamp at which the session ended (accurate to 5 seconds).
    Total Time - the absolute time that the application has been in the foreground in seconds.
    Last Time - the timestamp at which the application was previously launched.