def encodeFeatureList()

in spark/spark-tensorflow-connector/src/main/scala/org/tensorflow/spark/datasources/tfrecords/serde/DefaultTfRecordRowEncoder.scala [153:200]
41 lines of code
9 McCabe index (conditional complexity)

  def encodeFeatureList(row: Row, structField: StructField, index: Int): FeatureList = {
    val featureList = structField.dataType match {
      case ArrayType(ArrayType(IntegerType, _), _) =>
        val longArrays = ArrayData.toArrayData(row.get(index)).array.map {arr =>
          ArrayData.toArrayData(arr).toIntArray().map(_.toLong).toSeq
        }
        Int64FeatureListEncoder.encode(longArrays)

      case ArrayType(ArrayType(LongType, _), _) =>
        val longArrays = ArrayData.toArrayData(row.get(index)).array.map {arr =>
          ArrayData.toArrayData(arr).toLongArray().toSeq
        }
        Int64FeatureListEncoder.encode(longArrays)

      case ArrayType(ArrayType(FloatType, _), _) =>
        val floatArrays = ArrayData.toArrayData(row.get(index)).array.map {arr =>
          ArrayData.toArrayData(arr).toFloatArray().toSeq
        }
        FloatFeatureListEncoder.encode(floatArrays)

      case ArrayType(ArrayType(DoubleType, _), _) =>
        val floatArrays = ArrayData.toArrayData(row.get(index)).array.map {arr =>
          ArrayData.toArrayData(arr).toDoubleArray().map(_.toFloat).toSeq
        }
        FloatFeatureListEncoder.encode(floatArrays)

      case ArrayType(ArrayType(DecimalType(), _), _) =>
        val floatArrays = ArrayData.toArrayData(row.get(index)).array.map {arr =>
          ArrayData.toArrayData(arr).toArray[Decimal](DataTypes.createDecimalType()).map(_.toFloat).toSeq
        }
        FloatFeatureListEncoder.encode(floatArrays)

      case ArrayType(ArrayType(StringType, _), _) =>
        val arrayData = ArrayData.toArrayData(row.get(index)).array.map {arr =>
          ArrayData.toArrayData(arr).toArray[String](ObjectType(classOf[String])).toSeq.map(_.getBytes)
        }.toSeq
        BytesFeatureListEncoder.encode(arrayData)

      case ArrayType(ArrayType(BinaryType, _), _) =>
        val arrayData = ArrayData.toArrayData(row.get(index)).array.map {arr =>
          ArrayData.toArrayData(arr).toArray[Array[Byte]](BinaryType).toSeq
        }.toSeq
        BytesFeatureListEncoder.encode(arrayData)

      case _ => throw new RuntimeException(s"Cannot convert row element ${row.get(index)} to FeatureList.")
    }
    featureList
  }