一种方法是创建一个新类EmployeeAvailabilityPattern，它有一个方法appliesToShift(Shift)，如果Shift匹配可用性模式，则返回true，否则返回false。然后匹配EmployeeAvailabilityPattern的约束如下所示：

private static BiConstraintStream<EmployeeAvailabilityPattern, Shift> getConstraintStreamWithAvailabilityPatternIntersections(
            ConstraintFactory constraintFactory, EmployeeAvailabilityState employeeAvailabilityState) {
    return constraintFactory.forEach(EmployeeAvailabilityPattern.class)
        .filter(pattern -> pattern.getState() == employeeAvailabilityState)
        .join(Shift.class,
              equal(EmployeeAvailabilityPattern::getEmployee, Shift::getEmployee))
        .filter((pattern, shift) -> pattern.appliesToShift(shift));
}

Constraint unavailablePatternEmployeeTimeSlot(ConstraintFactory constraintFactory) {
    return getConstraintStreamWithAvailabilityPatternIntersections(constraintFactory, UNAVAILABLE)
               .penalizeConfigurableLong(CONSTRAINT_UNAVAILABLE_TIME_SLOT_FOR_AN_EMPLOYEE,
                        ((employeeAvailability, shift) -> shift.getLengthInMinutes()));
}