* Overrides compare method. Can compare <code>DateTime</code>
* structures.
*/
protected boolean compare(Object ob1, Object ob2) {
if (ob1 instanceof DateTime && ob2 instanceof DateTime) {
DateTime dt1 = (DateTime)ob1;
DateTime dt2 = (DateTime)ob2;
return dt1.Year == dt2.Year
&& dt1.Month == dt2.Month
&& dt1.Day == dt2.Day
&& dt1.Hours == dt2.Hours