How to find out if a cell contains a Date

[Oliver Fuerniss]

Hello,
i am using the poi dev version 1.5.0 and i have the following questions:
Is there an way to find out, if the current cell contains a date? The method 
getCellType() delivers always CELL_TYPE_NUMERIC for my dates. Why is there no 
constant for cell.getCellType() like HSSFCell.CELL_TYPE_DATETIME? 
Also cell.getCellStyle().getDataFormat() is always 0 (General). 
Thanx 
  Oliver