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/*
* 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.spark.serializer
import java.io._
import java.nio.ByteBuffer
import scala.reflect.ClassTag
import org.apache.spark.SparkConf
import org.apache.spark.annotation.DeveloperApi
import org.apache.spark.util.ByteBufferInputStream
import org.apache.spark.util.Utils
private[spark] class JavaSerializationStream(out: OutputStream, counterReset: Int)
extends SerializationStream {
private val objOut = new ObjectOutputStream(out)
private var counter = 0
/**
* Calling reset to avoid memory leak:
* http://stackoverflow.com/questions/1281549/memory-leak-traps-in-the-java-standard-api
* But only call it every 10,000th time to avoid bloated serialization streams (when
* the stream 'resets' object class descriptions have to be re-written)
*/
def writeObject[T: ClassTag](t: T): SerializationStream = {
objOut.writeObject(t)
if (counterReset > 0 && counter >= counterReset) {
objOut.reset()
counter = 0
} else {
counter += 1
}
this
}
def flush() { objOut.flush() }
def close() { objOut.close() }
}
private[spark] class JavaDeserializationStream(in: InputStream, loader: ClassLoader)
extends DeserializationStream {
private val objIn = new ObjectInputStream(in) {
override def resolveClass(desc: ObjectStreamClass) =
Class.forName(desc.getName, false, loader)
}
def readObject[T: ClassTag](): T = objIn.readObject().asInstanceOf[T]
def close() { objIn.close() }
}
private[spark] class JavaSerializerInstance(counterReset: Int) extends SerializerInstance {
def serialize[T: ClassTag](t: T): ByteBuffer = {
val bos = new ByteArrayOutputStream()
val out = serializeStream(bos)
out.writeObject(t)
out.close()
ByteBuffer.wrap(bos.toByteArray)
}
def deserialize[T: ClassTag](bytes: ByteBuffer): T = {
val bis = new ByteBufferInputStream(bytes)
val in = deserializeStream(bis)
in.readObject().asInstanceOf[T]
}
def deserialize[T: ClassTag](bytes: ByteBuffer, loader: ClassLoader): T = {
val bis = new ByteBufferInputStream(bytes)
val in = deserializeStream(bis, loader)
in.readObject().asInstanceOf[T]
}
def serializeStream(s: OutputStream): SerializationStream = {
new JavaSerializationStream(s, counterReset)
}
def deserializeStream(s: InputStream): DeserializationStream = {
new JavaDeserializationStream(s, Utils.getContextOrSparkClassLoader)
}
def deserializeStream(s: InputStream, loader: ClassLoader): DeserializationStream = {
new JavaDeserializationStream(s, loader)
}
}
/**
* :: DeveloperApi ::
* A Spark serializer that uses Java's built-in serialization.
*
* Note that this serializer is not guaranteed to be wire-compatible across different versions of
* Spark. It is intended to be used to serialize/de-serialize data within a single
* Spark application.
*/
@DeveloperApi
class JavaSerializer(conf: SparkConf) extends Serializer with Externalizable {
private var counterReset = conf.getInt("spark.serializer.objectStreamReset", 10000)
def newInstance(): SerializerInstance = new JavaSerializerInstance(counterReset)
override def writeExternal(out: ObjectOutput) {
out.writeInt(counterReset)
}
override def readExternal(in: ObjectInput) {
counterReset = in.readInt()
}
}
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