@Override
    public final void toXContent(XContentBuilder builder) throws IOException {
        builder.startObject();
        doXContent(builder);
        builder.endObject();
    }
@see io.apiman.manager.api.es.util.QueryBuilder#toXContent(io.apiman.manager.api.es.util.XContentBuilder)
manager/api/es/src/main/java/io/apiman/manager/api/es/util/AbstractQueryBuilder.java