this.shardNum = shardNum;
this.numShards = numShards;
this.fileName = fileName;
File f = new File(ChiFilenames.getFilenameShardsAdj(fileName, shardNum, numShards));
adjFile = new RandomAccessFile(f.getAbsolutePath(), "r", 64 * 1024);
index = new ShardIndex(f);
}