public HdfsSystemDescriptor withConsumerGroupPattern(String groupPattern) {
    this.consumerGroupPattern = Optional.ofNullable(StringUtils.stripToNull(groupPattern));
    return this;
  }
Group pattern used by directory partitioner for advanced partitioning.
@param groupPattern group parttern for HDFS consumer inputs.
@return this system descriptor
samza-hdfs/src/main/java/org/apache/samza/system/hdfs/descriptors/HdfsSystemDescriptor.java