public String asUiFriendlyString() {
        // make partIndex one based
        return "reference stream: " + streamId +
                ":" + (partIndex + 1) +
                " pipeline: " +
                (pipelineDocRef.getName() != null
                        ? pipelineDocRef.getName()
                        : pipelineDocRef.getUuid());
    }
One based part in the stream.
stroom-pipeline/src/main/java/stroom/pipeline/refdata/store/RefStreamDefinition.java