DownloadManager core_download = core_file.getDownloadManager();
if ( core_download.getTorrent() == null ){
throw( new DownloadException( "Torrent invalid" ));
}
if ( core_download.isDestroyed()){
Debug.out( "Download has been removed" );
throw( new DownloadException( "Download has been removed" ));
}
synchronized( DiskManagerChannelImpl.class ){
channel_id = channel_id_next++;