org.apache.flink.runtime.types.JavaIterableWrapperSerializer.scala Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.flink.runtime.types
import _root_.java.lang.{Iterable => JIterable}
import com.twitter.chill.{Input, KSerializer, Kryo, Output}
/*
This code is copied as is from Twitter Chill 0.7.4 because we need to user a newer chill version
but want to ensure that the serializers that are registered by default stay the same.
The only changes to the code are those that are required to make it compile and pass checkstyle
checks in our code base.
*/
/**
* A Kryo serializer for serializing results returned by asJavaIterable.
*
* The underlying object is scala.collection.convert.Wrappers$IterableWrapper.
* Kryo deserializes this into an AbstractCollection, which unfortunately doesn't work.
*
* Ported from Apache Spark's KryoSerializer.scala.
*/
private class JavaIterableWrapperSerializer extends KSerializer[JIterable[_]] {
import JavaIterableWrapperSerializer._
override def write(kryo: Kryo, out: Output, obj: JIterable[_]): Unit = {
// If the object is the wrapper, simply serialize the underlying Scala Iterable object.
// Otherwise, serialize the object itself.
if (obj.getClass == wrapperClass && underlyingMethodOpt.isDefined) {
kryo.writeClassAndObject(out, underlyingMethodOpt.get.invoke(obj))
} else {
kryo.writeClassAndObject(out, obj)
}
}
override def read(kryo: Kryo, in: Input, clz: Class[JIterable[_]]): JIterable[_] = {
kryo.readClassAndObject(in) match {
case scalaIterable: Iterable[_] =>
scala.collection.JavaConversions.asJavaIterable(scalaIterable)
case javaIterable: JIterable[_] =>
javaIterable
}
}
}
private object JavaIterableWrapperSerializer {
// The class returned by asJavaIterable (scala.collection.convert.Wrappers$IterableWrapper).
val wrapperClass = scala.collection.JavaConversions.asJavaIterable(Seq(1)).getClass
// Get the underlying method so we can use it to get the Scala collection for serialization.
private val underlyingMethodOpt = {
try Some(wrapperClass.getDeclaredMethod("underlying")) catch {
case e: Exception =>
None
}
}
}