public boolean nextKeyValue()

in core/src/main/java/com/twitter/elephantbird/mapreduce/input/combine/CompositeRecordReader.java [100:138]
25 lines of code
8 McCabe index (conditional complexity)

  public boolean nextKeyValue() throws IOException, InterruptedException {
    // This is essentially tail recursion, but java style
    while (true) {
      // No record reader, and there are no more record readers. No more KV's
      if (currentRecordReader == null && recordReaders.isEmpty()) {
        return false;
      } else if (currentRecordReader != null) {
        // We have a record reader, and it is either done, or we have more values.
        if (currentRecordReader.nextKeyValue()) {
          return true;
        }
        currentRecordReader.close();
        // Rely on the rest of the loop to get a next currentRecordReader, if there is one available.
        currentRecordReader = null;
      }

      // At this point, there is no currentRecordReader and no more recordReaders. No more KVs.
      if (recordReaders.isEmpty()) {
        return false;
      }
      currentRecordReader = recordReaders.remove().createRecordReader();
      currentRecordReaderIndex++;
      // The DeprecatedInputFormatWrapper has a check in it which ensures that the key and value
      // objects of the underlying MapredInputFormatCompatible are the same. Thus, we rely on the
      // very first RecordReader that we instantiate to create the underlying objects which we
      // will use for the rest of the process.
      if (!haveInitializedFirstRecordReader) {
        key = currentRecordReader.getCurrentKey();
        value = currentRecordReader.getCurrentValue();
        haveInitializedFirstRecordReader = true;
      } else {
        // This call is purely for interop with DeprecatedInputFormatWrapper. It ensures that a pair of
        // key value objects which were set by a calling function are passed to the new delegate so that it
        // will be consistent the entire time.
        setKeyValue(key, value);
      }
      // We will loop again and see if there is a nextKeyValue
    }
  }