DefaultGlazedListsFilterStrategy.getTextFilterator().TextFilterator
...
Object displayValue = converter.canonicalToDisplayValue(cellData);

DefaultDisplayConverter.canonicalToDisplayValue()
...
return sourceValue != null ? sourceValue.toString() : "";

configRegistry.registerConfigAttribute( //
    FilterRowConfigAttributes.FILTER_DISPLAY_CONVERTER, //
    aNormalDisplayConverter, //
    DisplayMode.NORMAL, //
    FilterRowDataLayer.FILTER_ROW_COLUMN_LABEL_PREFIX + aColumnIndex);

public class CalenderTimeToTextConverter extends DisplayConverter {

    private static final String BITE_TIME_FORMAT = "yyyy'-'MM'-'dd' 'HH':'mm':'ssZ";
    private final SimpleDateFormat aSimpleDateFormat;

    public CalenderTimeToTextConverter() {
        aSimpleDateFormat = new SimpleDateFormat(BITE_TIME_FORMAT);
    }

    @Override
    public Object canonicalToDisplayValue(Object canonicalValue) {

        String res = "";

        if (canonicalValue instanceof Calendar) {
            Calendar cal = (Calendar) canonicalValue;
            res = aSimpleDateFormat.format(cal.getTime());
        }
        else {
            if (null == canonicalValue) {
                res = "*null*";
            }
            else if (canonicalValue instanceof String) {
                res = (String) canonicalValue;
            }
            else {
                System.out.println("'canonicalValue' is neither a Calendar nor a String: \"" + canonicalValue + "\"");
                res = canonicalValue.toString();
            }
        }

        return res;
    }

    @Override
    public Object displayToCanonicalValue(Object displayValue) {

        Calendar res = null;

        if (displayValue instanceof String) {
            String stringValue = (String) displayValue;
            try {
                Date date = aSimpleDateFormat.parse(stringValue);
                Calendar.Builder cb = new Calendar.Builder();
                cb.setInstant(date);
                res = cb.build();
            }
            catch (ParseException e) {
                System.out.println("Failed to parse the string \"" + stringValue + "\" into a Calendar instance.");
            }
        }
        return res;
    }
}

configRegistry.registerConfigAttribute(
    FilterRowConfigAttributes.TEXT_MATCHING_MODE,
    TextMatchingMode.CONTAINS, DisplayMode.NORMAL,
    FilterRowDataLayer.FILTER_ROW_COLUMN_LABEL_PREFIX + 5);