public void setCompressionMethod(final String compressionMethod) {
        if (!NullSafe.isBlankString(compressionMethod)) {
            if (CompressionUtil.isSupportedCompressor(compressionMethod)) {
                this.compressionMethod = compressionMethod;
            } else {
                String errorMsg = "Unsupported compression method: " + compressionMethod;
                throw ProcessException.create(errorMsg);
            }
        }
    }
@param attributeMapOverride If supplied these attributes will be used rather than those in the metaHolder
stroom-pipeline/src/main/java/stroom/pipeline/writer/OutputFactory.java