@Override
    public NullOrder getNullOrder() {
        return nullOrder;
    }
The default implementation of the {@link ReferenceFieldComparator} interface.

@param <ENTITY>  the entity type
@param <D>       the database type
@param <V>       the value type

@author  Per Minborg
@author  Emil Forslund
@since   2.2.0
runtime-parent/runtime-field/src/main/java/com/speedment/runtime/field/internal/comparator/ReferenceFieldComparatorImpl.java