Generic class defining an interval (i.e. range) of a comparable type. An interval is
a contiguous subrange of a comparable base type. Used to define intervals of dates,
times, quantities (whose units match) and so on.
The type parameter, T, must be a descendant of the type DV_ORDERED, which is
necessary (but not sufficient) for instances to be compared (strictly_comparable is
also needed).
Without the DV_INTERVAL class, quite a few more DV_ classes would be needed to
express logical intervals, namely interval versions of all the date/time classes, and
of quantity classes. Further, it allows the semantics of intervals to be stated in one
place unequivocally, including the conditions for strict comparison.

The basic semantics are derived from the class INTERVAL<T>, described in the
support RM.

Declaration :

• C++ : template<class DV_ORDERED> class DV_INTERVAL : public DATA_VALUE, public INTERVAL<DV_ORDERED>
• Java : public class DV_INTERVAL<DV_ORDERED> extends DATA_VALUE implements INTERVAL<DV_ORDERED>

Artifact : DV_INTERVAL