private String getFeedName() {
        if (feedHolder != null) {
            final FeedHolder fh = feedHolder.get();
            if (fh != null) {
                return fh.getFeedName();
            }
        }
        return null;
    }
Used when XSLT is supplied (for xsl:output)
stroom-pipeline/src/main/java/stroom/pipeline/writer/XMLWriter.java