@ValidationMethod(message = "referenceFeed docRef must have a UUID or a name. The lookup will " +
                                    "be faster if both are supplied")
        @JsonIgnore
        public boolean isValidFeedDocRef() {
            return referenceFeed != null && (
                    (referenceFeed.getUuid() != null && !referenceFeed.getUuid().isEmpty()) ||
                    (referenceFeed.getName() != null && !referenceFeed.getName().isEmpty()));
        }
@return data string or epoch ms
stroom-pipeline/src/main/java/stroom/pipeline/refdata/RefDataLookupRequest.java