The OpenEdge Hive

I'm reading Martin Fowler's refactoring and will work out some of his methods (which also apply to building new software) in this blog. Read this to get some background info:

http://sourcemaking.com/refactoring/introduce-parameter-object
http://www.refactoring.com/catalog/introduceParameterObject.html
http://martinfowler.com/ap2/range.html

Below a simple daterangeparameter object, and therebelow a procedure using the daterange object.

CLASS dateRange FINAL:

  DEFINE PRIVATE VARIABLE StartTime AS DATETIME NO-UNDO.
  DEFINE PRIVATE VARIABLE EndTime   AS DATETIME NO-UNDO.

  CONSTRUCTOR dateRange (tStart AS DATETIME, tEnd AS DATETIME):
    ASSIGN StartTime = tStart
           EndTime   = tEnd.
  END CONSTRUCTOR. 

  METHOD PUBLIC DATETIME Start ():
    RETURN StartTime.
  END METHOD.

  METHOD PUBLIC DATETIME End ():
    RETURN EndTime.
  END METHOD.

  METHOD PUBLIC DATE dStart ():
    RETURN DATE(StartTime).
  END METHOD.

  METHOD PUBLIC DATE dEnd ():
    RETURN DATE(EndTime).
  END METHOD.

  METHOD PUBLIC INT64 Intv (intervalUnit AS CHARACTER):
    RETURN INTERVAL(EndTime,StartTime,intervalUnit).
  END METHOD.

  METHOD PUBLIC LOGICAL EndAfterStart():
    /* Endtime = ? is interpreted as 'far far in the future' */
    RETURN IF EndTime > StartTime THEN TRUE
        ELSE IF StartTime NE ? AND EndTime = ? THEN TRUE
        ELSE ?.
  END METHOD.

  METHOD PUBLIC LOGICAL Includes(IncludedInRange AS DATETIME):
    RETURN EndAfterStart() /* otherwise it's not a range */
        AND (IncludedInRange > StartTime 
                 AND (EndTime = ? OR IncludedInRange < EndTime)
            ).
  END METHOD.
END CLASS.


/* a procedure using the daterange object: */
RUN a (NEW daterange(12/30/09,01/02/10)). 

PROCEDURE a:
    DEFINE INPUT PARAMETER dateRange AS CLASS dateRange NO-UNDO.
    MESSAGE DATE(dateRange:Start()) daterange:endafterstart() daterange:intv('hours') daterange:includes(11/30/09) 
        VIEW-AS ALERT-BOX INFO BUTTONS OK.
END PROCEDURE.