Grid only saving 3 decimal places when mapping column to BigDecimal or Doub

It's the StringToBigDecimalConverter that is converting BigDecimal to String using rounding. You need to provide your own converter that has more decimal places reserved for presentation.

Thanks, Johannes. I'm sorry to ask, but do you have any insight as to how this can be done? I found examples of the converter online, and see how to fix it, but am unclear as to how to bind my new converter to the Grid. 

OK, now I feel stupid. I am obviously close, but I can't figure out what I'm doing wrong. I have implemented my converter, and know it is being called because I can see convertToPresentation is being called, but nothing I do seems to effect the number of decimal places it recognizes. 

I have overriden all the functions in AbstractStringToNumberConverter, and still nothing. Outside of convertToPresentation, it seems the other functions are dead. Here's where I'm at now (Its weird, I know, but I've tried a lot), maybe someone can point me in the right direction?

public class StringToBigDecimalConverter extends AbstractStringToNumberConverter<BigDecimal> {

    @Override
    protected NumberFormat getFormat(Locale locale) {
        NumberFormat numberFormat = super.getFormat(locale);
        if (numberFormat instanceof DecimalFormat) {
            ((DecimalFormat) numberFormat).setParseBigDecimal(true);
        }

        return numberFormat;

    }

    @Override
    public String convertToPresentation(BigDecimal value, Class<? extends String> targetType, Locale locale)
            throws ConversionException {
        if (value == null) {
            return null;
        }
System.out.println(" ... presentation ... " + value);
        return value.setScale(4, RoundingMode.HALF_UP).toString();
    }

    @Override
    protected Number convertToNumber(String value, Class<? extends Number> targetType, Locale locale)
            throws ConversionException {
        if (value == null) {
            return null;
        }
System.out.println(" ... number ... " + value);
        return Util.toBigDecimal(value).setScale(4, RoundingMode.HALF_UP);
    }

    @Override
    public BigDecimal convertToModel(String value, Class<? extends BigDecimal> aClass, Locale locale) throws ConversionException {
        BigDecimal retval = Util.toBigDecimal(value).setScale(4, RoundingMode.HALF_UP);
System.out.println(" ... model ... " + value);
        return retval;
    }

    @Override
    public Class<BigDecimal> getModelType() {
        return BigDecimal.class;
    }

    @Override
    public Class<String> getPresentationType() {
        return String.class;
    }
}

Just to be sure, have you added the converter also to the editor textbox?

To the textbox? ... No, I don't think so. I added it to the Grid's column like so:

myGrid.getColumn("nav").setConverter(new StringToBigDecimalConverter());

Is there another step to this?

I'm not 100% sure, but I think Grid doesn't assign the column's converter to the editor field created for the column. Here's an old (but still valid) article on how to assign your own converter as the default for a type. You could try if that fixes your issue. https://vaadin.com/wiki/-/wiki/Main/Changing+the+default+converters+for+an+application