import com.fasterxml.sort.DataReader; //导入依赖的package包/类
public SortedPathIterator(final Iterator<Path> iter) throws IOException {
  SortConfig config = new SortConfig().withMaxMemoryUsage(1000000);
  Sorter sorter = new TextFileSorter(config);

  DataReader<byte[]> reader = new DataReader<byte[]>() {
    @Override
    public byte[] readNext() throws IOException {
      if (!iter.hasNext()) {
        return null;
      }
      return iter.next().toString().getBytes(Charsets.UTF_8);
    }
    @Override
    public void close() throws IOException {}
    @Override
    public int estimateSizeInBytes(byte[] item) { return item.length; }
  };

  this.sortedIter = sorter.sort(reader);
}
 

import com.fasterxml.sort.DataReader; //导入依赖的package包/类
@Override
public DataReader<R> constructReader(InputStream in) throws IOException {
    MappingIterator<R> it = _reader.with(_schema).readValues(in);
    return new Reader<R>(it);
}
 

import com.fasterxml.sort.DataReader; //导入依赖的package包/类
@Override
public DataReader<T> constructReader(InputStream in) throws IOException {
  return new CustomReader<T>(in);
}
 

import com.fasterxml.sort.DataReader; //导入依赖的package包/类
@Override
public DataReader<SortKey> constructReader(InputStream arg0)
        throws IOException {
    return new KeyReader(arg0);
}
 

import com.fasterxml.sort.DataReader; //导入依赖的package包/类
@Override
public DataReader<IdAndVersion> constructReader(final InputStream inputStream) throws IOException {
    return new IdAndVersionDataReader(factory, new ObjectInputStream(inputStream));

}