public CSVBuilder update(UIComponent component, String expressions) {
        if (LangUtils.isNotBlank(expressions)) {
            String resolvedExpressions = SearchExpressionUtils.resolveClientIdsForClientSide(context, component, expressions);
            buffer.append(",u:'").append(resolvedExpressions).append("'");
        }

        return this;
    }
Helper to generate javascript code of a client side validation*
primefaces/src/main/java/org/primefaces/util/CSVBuilder.java