Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/1338#discussion_r15386068
--- Diff:
core/src/main/scala/org/apache/spark/api/python/PythonHadoopUtil.scala ---
@@ -92,6 +104,46 @@ private[python] class DefaultConverter extends
Converter[Any, Any] {
}
}
+/**
+ * A converter that converts common types to
[[org.apache.hadoop.io.Writable]]. Note that array
+ * types are not supported since the user needs to subclass
[[org.apache.hadoop.io.ArrayWritable]]
+ * to set the type properly. See
[[org.apache.spark.api.python.DoubleArrayWritable]] and
+ * [[org.apache.spark.api.python.DoubleArrayToWritableConverter]] for an
example. They are used in
+ * PySpark RDD `saveAsNewAPIHadoopFile` doctest.
+ */
+private[python] class JavaToWritableConverter extends Converter[Any,
Writable] {
+
+ /**
+ * Converts common data types to [[org.apache.hadoop.io.Writable]]. Note
that array types are not
+ * supported out-of-the-box.
+ */
+ private def convertToWritable(obj: Any): Writable = {
+ import collection.JavaConversions._
+ obj match {
+ case i: java.lang.Integer => new IntWritable(i)
+ case d: java.lang.Double => new DoubleWritable(d)
+ case l: java.lang.Long => new LongWritable(l)
+ case f: java.lang.Float => new FloatWritable(f)
+ case s: java.lang.String => new Text(s)
+ case b: java.lang.Boolean => new BooleanWritable(b)
+ case aob: Array[Byte] => new BytesWritable(aob)
+ case null => NullWritable.get()
+ case map: java.util.Map[_, _] =>
+ val mapWritable = new MapWritable()
+ map.foreach { case (k, v) =>
+ mapWritable.put(convertToWritable(k), convertToWritable(v))
+ }
+ mapWritable
+ case other => throw new SparkException(s"Data of type $other cannot
be used")
--- End diff --
This comment also applies to the other unsupported type messages added in
this PR.
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