/** 
 * Converts the measuring date of the second column into the Age
 * of the patient at the measuring day, using the birthday calculated
 * in the function setBirthday.
 * 
 * NEEDED FUNCTIONS:
 * - getBirthdayOfCurrentPatient()
 * - calculateAge()
 * 
 * @param datatable:
 * The table, that shall be manipulated
 * 
 * @param columnToConvert:
 * the index of the column, that shall be converted 
 * from a date to the age at that date (index 0 = first column)
 */
function convertColumnDateToAge (datatable, columnToConvert) {
   /* ======================================== */
   // IMPORTS
   importPackage(java.util);
   importPackage(java.lang);
   importPackage(java.text);
 
 
   var tableModel = datatable.getModel();
 
   // get the patients birthday
   var calendar_birthday = getBirthdayOfCurrentPatient();
   var calendar_creationDate = new GregorianCalendar();
 
   /* a date formater to format a date into a String 
    * and parse a formated String into a date
    */
   var formater = DateFormat.getDateInstance(
         DateFormat.SHORT);
 
   // replace the creation date with the patient's age in every row
   for (var int_row = 0; int_row < tableModel.getRowCount(); int_row++) {
      /* ---------------------------------------- */
      try {
         // make a Date resp. Calendar out of the formated String
         calendar_creationDate.setTime(
               formater.parse(tableModel.getValueAt(int_row, columnToConvert)));
      } catch (err) {
         // the String couldn't be parsed
//         println("manipulateTable(): " + err);
         continue;
      }
 
      // calculate the patient's age out of the creation date and birthdate
      var int_age = new Integer(calculateAge(calendar_birthday, calendar_creationDate));
 
      // replace the date in the column age with the calculated age
      tableModel.setValueAt(int_age, int_row, columnToConvert);
      /* ---------------------------------------- */
   }
   /* ======================================== */
}