default OrderType getOrderType() {
        return getAsString(HasOrderTypeUtil.ORDER_TYPE)
            .map(OrderType::valueOf)
            .orElse(OrderType.ASC);
    }
Returns the type of the ordering used in this {@link Document}. The 
{@code orderType} is an enum value located under the {@link HasOrderTypeUtil#ORDER_TYPE}
key.

@return  the order type
runtime-parent/runtime-config/src/main/java/com/speedment/runtime/config/trait/HasOrderType.java