private long getDate(final String fieldName, final String value) {
        try {
            return DateExpressionParser.parse(value, dateTimeSettings)
                    .map(dt -> dt.toInstant().toEpochMilli())
                    .orElseThrow(() -> new SearchException("Expected a standard date value for field \"" + fieldName
                            + "\" but was given string \"" + value + "\""));
        } catch (final RuntimeException e) {
            throw new SearchException("Expected a standard date value for field \"" + fieldName
                    + "\" but was given string \"" + value + "\"");
        }
    }
Convert our query objects to a LUCENE query.
stroom-index/stroom-index-lucene980/src/main/java/stroom/index/lucene980/SearchExpressionQueryBuilder.java