Customer

This class should now implement the Comparable interface. Customer instances should be ordered by their last name, then first name, and finally the name of their associated building.

toString() - Add this method that returns a String with the following format: ,

Reading

This class should now implement the Comparable interface. Reading instances should be ordered by their timestamp.

XmlHandler

The following methods should be updated:

startElement() - The handler logic should be modified such that it can now create and associate Customer, Building, Room, Device, and Reading objects.

endElement() - Modify this method such that the current customer instance is added to the ArrayList of customers when a closing customer element is encountered.