text: public static DVConstraint createDateConstraint(int comparisonOperator, String expr1, String expr2, String dateFormat) {if (expr1 == null) {throw new IllegalArgumentException("expr1 must be supplied");}OperatorType.validateSecondArg(comparisonOperator, expr2);SimpleDateFormat df = null;if (dateFormat != null) {df = new SimpleDateFormat(dateFormat, LocaleUtil.getUserLocale());df.setTimeZone(LocaleUtil.getUserTimeZone());}String formula1 = getFormulaFromTextExpression(expr1);Double value1 = formula1 == null ? convertDate(expr1, df) : null;String formula2 = getFormulaFromTextExpression(expr2);Double value2 = formula2 == null ? convertDate(expr2, df) : null;return new DVConstraint(ValidationType.DATE, comparisonOperator, formula1, formula2, value1, value2, null);}