public static List<ExpressionTerm> terms(final ExpressionOperator expressionOperator,
                                             final Collection<String> fieldNames) {
        final List<ExpressionTerm> terms = new ArrayList<>();
        addTerms(expressionOperator, fieldNames, terms);
        return terms;
    }
@return True if there are at least one enabled term under the expressionOperator
stroom-query/stroom-query-api/src/main/java/stroom/query/api/ExpressionUtil.java