CompositeInputSplit.java 文件源码

/**
 * {@inheritDoc}
 * @throws IOException If the child InputSplit cannot be read, typically
 *                     for failing access checks.
 */
@SuppressWarnings("unchecked")  // Generic array assignment
public void readFields(DataInput in) throws IOException {
  int card = WritableUtils.readVInt(in);
  if (splits == null || splits.length != card) {
    splits = new InputSplit[card];
  }
  Class<? extends InputSplit>[] cls = new Class[card];
  try {
    for (int i = 0; i < card; ++i) {
      cls[i] =
        Class.forName(Text.readString(in)).asSubclass(InputSplit.class);
    }
    for (int i = 0; i < card; ++i) {
      splits[i] = ReflectionUtils.newInstance(cls[i], null);
      SerializationFactory factory = new SerializationFactory(conf);
      Deserializer deserializer = factory.getDeserializer(cls[i]);
      deserializer.open((DataInputStream)in);
      splits[i] = (InputSplit)deserializer.deserialize(splits[i]);
    }
  } catch (ClassNotFoundException e) {
    throw new IOException("Failed split init", e);
  }
}