GAE JDO serialized versus JSON

GAE JDO serialized bug.scala

import java.lang.{Long => JLong, Integer => JInteger, Double => JDouble}
import java.util.{Map => JMap, HashMap => JHashMap, List => JList, LinkedList => JLinkedList}
import javax.jdo.annotations._
import scala.collection.jcl.Conversions._

/**
 * This class tracks all the ratings of a single doctor
 * (the doctor is identified by country-region-firstName-lastName).
 */
@PersistenceCapable{val identityType = IdentityType.APPLICATION, val detachable = "true"}
class Doctor {
  def NULL = null // Workaround for NUCENHANCER-34.

  // ...

  /** Here we keep track of doctor's rating<br>
   * and keep the copy of some of the rating's data close for recalculations.<br> 
   * problem -> ratingKey -> fieldName (actLevStart|actLevEnd) -> fieldValue */
  @Persistent{val serialized = "true"}
  var ratings: JHashMap[String, JHashMap[JLong, DenormalizedRating]] = NULL
  // Will replace "ratings" if everything works. See
  // http://groups.google.ru/group/google-appengine-java/browse_frm/thread/747ceed8396c0ed8/9955970bd4c37ec6#9955970bd4c37ec6
  @Persistent private[this] var jsonRatings: String = NULL

  /** Access the "ratings" field, which is JSON-serialized. */
  def getRatings: JMap[String, JMap[JLong, DenormalizedRating]] = {
    import org.codehaus.jackson.`type`.TypeReference
    JDO.JACKSON_MAPPER.readValue (if (jsonRatings ne null) jsonRatings else "{}",
      new TypeReference[JMap[String, JMap[JLong, DenormalizedRating]]] {})
  }
  def setRatings (ratings: JMap[String, JMap[JLong, DenormalizedRating]]): Unit = {
    val sw = new java.io.StringWriter
    JDO.JACKSON_MAPPER.writeValue (sw, ratings)
    jsonRatings = sw.toString
  }

  // ...
}

// ...

  /** Copy the rating's data into the Doctor. */
  def updateDoctor (): Unit = if ((doctor ne null) && (actLevStart ne null) && (actLevEnd ne null)) {
    // Old version using serialized map, updates don't work!
    if (doctor.ratings eq null) doctor.ratings = new JHashMap
    if (!doctor.ratings.containsKey (problem)) doctor.ratings.put (problem, new JHashMap)
    doctor.ratings.get (problem) .put (id.getId, DenormalizedRating (actLevStart.intValue, actLevEnd.intValue))
    doctor.ratings = doctor.ratings.clone
      .asInstanceOf[JHashMap[String, JHashMap[JLong, DenormalizedRating]]]

    // New version using JSON serialization.
    val ratings = doctor.getRatings
    if (!ratings.containsKey (problem)) ratings.put (problem, new JHashMap)
    ratings.get (problem) .put (id.getId, DenormalizedRating (actLevStart.intValue, actLevEnd.intValue))
    doctor.setRatings (ratings)
  }