CommonStub.java 文件源码

protected void readObject(Writable obj, DataInputStream inStream) throws IOException {
  int numBytes = WritableUtils.readVInt(inStream);
  byte[] buffer;
  // For BytesWritable and Text, use the specified length to set the length
  // this causes the "obvious" translations to work. So that if you emit
  // a string "abc" from C++, it shows up as "abc".
  if (obj instanceof BytesWritable) {
    buffer = new byte[numBytes];
    inStream.readFully(buffer);
    ((BytesWritable) obj).set(buffer, 0, numBytes);
  } else if (obj instanceof Text) {
    buffer = new byte[numBytes];
    inStream.readFully(buffer);
    ((Text) obj).set(buffer);
  } else {
    obj.readFields(inStream);
  }
}