private float getFloat(final String fieldName, final String value) {
        try {
            return Float.parseFloat(value);
        } catch (final NumberFormatException e) {
            throw new SearchException(
                    "Expected a numeric value for field \"" + fieldName + "\" but was given string \"" + value + "\"");
        }
    }
Convert our query objects to a LUCENE query.
stroom-index/stroom-index-lucene553/src/main/java/stroom/index/lucene553/SearchExpressionQueryBuilder.java