| Class | Description | 
                            | BaseDuration | Base class for date and time durations. | 
                            | BaseDuration.From |  | 
                            | DatumDependentDuration | DatumDependentDuration represents durations whose length in milliseconds 
 cannot be determined without knowing the datum point. | 
                            | Duration | Duration represents time periods which have values independent of the context. | 
                            | TimeCategory | Apply a number of methods to allow convenient Date/Time manipulation,such as: 
 use (groovy.time.TimeCategory) {
     // application on numbers:
     println 1.minute.from.now
     println 10.hours.ago | 
                            | TimeDatumDependentDuration | TimeDatumDuration represents a time period which results from an
 arithmetic operation between a TimeDuration object and a DatumDuration object | 
                            | TimeDuration | TimeDuration represents time periods expressed in units of hours, minutes,
 seconds and milliseconds. |