是否可以为akka编写upickle序列化程序？

Question

我想使用upickle实现一个akka序列化程序，但我不确定它是否可行。要做到这一点，我需要实现一个序列化程序，如下所示：

import akka.serialization.Serializer
import upickle.default._

class UpickleSerializer extends Serializer {

    def includeManifest: Boolean = true
    def identifier = 1234567

    def toBinary(obj: AnyRef): Array[Byte] = {
        writeBinary(obj) // ???
    }

    def fromBinary(bytes: Array[Byte], clazz: Option[Class[_]]): AnyRef = {
        readBinary(bytes) // ???
    }
}

问题是，如果没有相关的Writer/Reader，我就无法调用Writer/readB进制。有什么方法可以根据object类来查找这些信息吗？

Answer 1

我找到了一种用反射来做这件事的方法。我的解决方案基于这样一个假设:任何需要序列化的对象都应该在其配套对象中定义一个ReadWriter：

class UpickleSerializer extends Serializer {

private var map = Map[Class[_], ReadWriter[AnyRef]]()

def includeManifest: Boolean = true
def identifier = 1234567

def toBinary(obj: AnyRef): Array[Byte] = {
    implicit val rw = getReadWriter(obj.getClass)
    writeBinary(obj)
}

def fromBinary(bytes: Array[Byte], clazz: Option[Class[_]]): AnyRef = {
    implicit val rw = lookup(clazz.get)
    readBinary[AnyRef](bytes)
}

private def getReadWriter(clazz: Class[_]) = map.get(clazz) match {
    case Some(rw) => rw
    case None =>
        val rw = lookup(clazz)
        map += clazz -> rw
        rw
}

private def lookup(clazz: Class[_]) = {
    import scala.reflect.runtime._
    val rootMirror = universe.runtimeMirror(clazz.getClassLoader)
    val classSymbol = rootMirror.classSymbol(clazz)
    val moduleSymbol = classSymbol.companion.asModule
    val moduleMirror = rootMirror.reflectModule(moduleSymbol)
    val instanceMirror = rootMirror.reflect(moduleMirror.instance)
    val members = instanceMirror.symbol.typeSignature.members
    members.find(_.typeSignature <:< typeOf[ReadWriter[_]]) match {
        case Some(rw) =>
            instanceMirror.reflectField(rw.asTerm).get.asInstanceOf[ReadWriter[AnyRef]]
        case None =>
            throw new RuntimeException("Not found")
    }
}

}

Answer 2

看看下面的文件，你应该有一些想法！

CborAkkaSerializer.scala

LocationAkkaSerializer.scala

注意：这些序列化程序正在使用cbor