public PartListDO(DownloadSourceDO downloadSourceDO) { valueHolderDO = downloadSourceDO; type = SOURCE_PARTLIST;
public PartListDO(DownloadDO downloadDO) { valueHolderDO = downloadDO; type = MAIN_PARTLIST;
    public PartListDO(DownloadSourceDO downloadSourceDO) {        valueHolderDO = downloadSourceDO;        type = SOURCE_PARTLIST;    }