@Override
    public void startStream() {
        super.startStream();
        // Pretty sure startStream is never called by the pipeline processing, so favour startProcessing
        // which is

        // build the definition of the stream that is being processed

        if (refDataLoaderHolder.getRefDataLoader() == null) {
            errorReceiverProxy.log(
                    Severity.FATAL_ERROR,
                    null,
                    getElementId(),
                    "RefDataLoader is missing",
                    null);
        }

        refStreamDefinition = refDataLoaderHolder.getRefDataLoader()
                .getRefStreamDefinition();

        LOGGER.debug("StartStream called, refStreamDefinition: {}", refStreamDefinition);
    }
This XML filter captures XML content that defines key, value maps to be
stored as reference data. The key, value map content is likely to have been
produced as the result of an XSL transformation of some reference data.
<p>
This filter will typically fire
stroom-pipeline/src/main/java/stroom/pipeline/refdata/ReferenceDataFilter.java