public String findIndefiniteField() {
        if (resourceType == ResourceType.ANY)
            return "Resource type is ANY.";
        if (resourceType == ResourceType.UNKNOWN)
            return "Resource type is UNKNOWN.";
        if (name == null)
            return "Resource name is NULL.";
        if (patternType == PatternType.MATCH)
            return "Resource pattern type is MATCH.";
        if (patternType == PatternType.UNKNOWN)
            return "Resource pattern type is UNKNOWN.";
        return null;
    }
@return a string describing any ANY or UNKNOWN field, or null if there is no such field.
clients/src/main/java/org/apache/kafka/common/resource/ResourcePatternFilter.java