code: @Override
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
      id = DBIDUtil.importInteger(in.read());
      values = new double[in.readInt()];
      for(int d = 0; d < values.length; d++) {
        values[d] = in.readDouble();
      }
    }
docs: Calls the super method and reads the values of this entry from the
  specified input stream.
  
  @param in the stream to read data from in order to restore the object
  @throws java.io.IOException if I/O errors occur
  @throws ClassNotFoundException If the class for an object being restored
  cannot be found.