public void setIndexName(final String indexName) {
        if (indexName == null || indexName.trim().isEmpty()) {
            this.indexName = null;
        } else {
            this.indexName = indexName;
        }
    }
@return A new builder for creating a {@link DocRef} for this document's type.
stroom-core-shared/src/main/java/stroom/search/elastic/shared/ElasticIndexDoc.java