InsuranceAgeCalculation

/**
* 
* Implements the standard calculation for the final age
* 
* @param birthDate
* @param contractBeginDate
* @return the technical age
* @throws InvalidBirthDateException
*/
private int calculateFinalAge(Calendar birthDate, Calendar contractBeginDate) throws InvalidBirthDateException{

     int birthYear = birthDate.get(Calendar.YEAR);
     int birthMonth = birthDate.get(Calendar.MONTH);

     int contractBeginYear = contractBeginDate.get(Calendar.YEAR);
     int contractBeginMonth = contractBeginDate.get(Calendar.MONTH);

     int tecAge;

     if(birthDate.after(contractBeginDate)){
          throw new InvalidBirthDateException("birthDate cannot be defined as being after the supplied contractBeginDate");
     } else {
          int yearDif = contractBeginYear - birthYear;
          int monthDif = contractBeginMonth - birthMonth;

          if(monthDif < 0){
          monthDif += 12;
          yearDif -= 1;
          }

          if(monthDif > 6){
               yearDif += 1;
          }

          tecAge = yearDif;

          return tecAge;
     }
}