ReduceContextImpl.java 文件源码

@Override
public void mark() throws IOException {
  if (getBackupStore() == null) {
    backupStore = new BackupStore<KEYIN,VALUEIN>(conf, taskid);
  }
  isMarked = true;
  if (!inReset) {
    backupStore.reinitialize();
    if (currentKeyLength == -1) {
      // The user has not called next() for this iterator yet, so
      // there is no current record to mark and copy to backup store.
      return;
    }
    assert (currentValueLength != -1);
    int requestedSize = currentKeyLength + currentValueLength + 
      WritableUtils.getVIntSize(currentKeyLength) +
      WritableUtils.getVIntSize(currentValueLength);
    DataOutputStream out = backupStore.getOutputStream(requestedSize);
    writeFirstKeyValueBytes(out);
    backupStore.updateCounters(requestedSize);
  } else {
    backupStore.mark();
  }
}