@SuppressWarnings("SizeReplaceableByIsEmpty")
    public String toInfoString() {
        final StringBuilder sb = new StringBuilder();
        if (displayName != null) {
            sb.append(displayName);
        } else if (subjectId != null) {
            sb.append(subjectId);
        } else if (fullName != null) {
            sb.append(fullName);
        }
        if (sb.length() > 0) {
            sb.append(" ");
        }
        sb.append("{");
        sb.append(uuid);
        sb.append("}");

        if (sb.length() > 0) {
            return sb.toString();
        }

        return toString();
    }
@return "Group" or "User" depending on type.
stroom-util-shared/src/main/java/stroom/util/shared/UserRef.java