Calculate the birth date form CodiceFiscale

CfDate.java

   public static GregorianCalendar getDateFromCF(String cf) {
		GregorianCalendar date = new GregorianCalendar();
		int anno = Integer.parseInt("19" + cf.substring(6, 8));
		date.set(GregorianCalendar.YEAR, anno);

		int month = 0;
		switch (Character.toUpperCase(cf.charAt(8))) {
			case 'A':
				month = GregorianCalendar.JANUARY;
				break;
			case 'B':
				month = GregorianCalendar.FEBRUARY;
				break;
			case 'C':
				month = GregorianCalendar.MARCH;
				break;
			case 'D':
				month = GregorianCalendar.APRIL;
				break;
			case 'E':
				month = GregorianCalendar.MAY;
				break;
			case 'H':
				month = GregorianCalendar.JUNE;
				break;
			case 'L':
				month = GregorianCalendar.JULY;
				break;
			case 'M':
				month = GregorianCalendar.AUGUST;
				break;
			case 'P':
				month = GregorianCalendar.SEPTEMBER;
				break;
			case 'R':
				month = GregorianCalendar.OCTOBER;
				break;
			case 'S':
				month = GregorianCalendar.NOVEMBER;
				break;
			case 'T':
				month = GregorianCalendar.DECEMBER;
				break;
			default:
				throw new IllegalArgumentException("Mese errato: " + cf.charAt(8));
		}
		date.set(GregorianCalendar.MONTH, month);


		int day = Integer.parseInt(cf.substring(9, 11));
		if (day > 40) {
			// woman
			day -= 40;
		}
		date.set(GregorianCalendar.DAY_OF_MONTH, day);

    	return date;
    }