Why can't I save this ODocument with embeddedset property to OrientDB?

Question

Accessing OrientDB 1.7-RC1 from Scala, when attempting to save an ODocument with an embeddedset of objects of a custom type, I get an exception saying that the corresponding field is of an incompatible type. I need help in figuring out what I'm doing wrong.

The code to create/save the ODocument looks as follows, it represents a Package which has an embeddedset of Dependency objects:

val myHashSet = new util.HashSet[models.Dependency]()
myHashSet.add(new models.Dependency("mydep", "1.0"))
val myVersion = new ODocument("Version")
  .field("id", "myversion")
  .field("dependencies", myHashSet)
myVersion.save()

This leads to the following exception being thrown:

com.orientechnologies.orient.core.exception.OValidationException: The field 'Version.dependencies' has been declared as EMBEDDEDSET but an incompatible type is used. Value: Dependency(mydep,1.0)
    at com.orientechnologies.orient.core.record.ORecordSchemaAwareAbstract.validateEmbedded(ORecordSchemaAwareAbstract.java:429) ~[orientdb-core-1.7-rc1.jar:1.7-rc1]
    at com.orientechnologies.orient.core.record.ORecordSchemaAwareAbstract.validateField(ORecordSchemaAwareAbstract.java:249) ~[orientdb-core-1.7-rc1.jar:1.7-rc1]
    at com.orientechnologies.orient.core.record.ORecordSchemaAwareAbstract.validate(ORecordSchemaAwareAbstract.java:71) ~[orientdb-core-1.7-rc1.jar:1.7-rc1]
    at com.orientechnologies.orient.core.record.impl.ODocument.save(ODocument.java:1357) ~[orientdb-core-1.7-rc1.jar:1.7-rc1]
    at com.orientechnologies.orient.core.record.impl.ODocument.save(ODocument.java:1347) ~[orientdb-core-1.7-rc1.jar:1.7-rc1]
    at com.orientechnologies.orient.core.record.impl.ODocument.save(ODocument.java:1336) ~[orientdb-core-1.7-rc1.jar:1.7-rc1]

I've declared the Version.dependencies embeddedset in the database's schema like this:

create property Version.dependencies embeddedset Dependency

The Dependency class definition looks as follows (it implements OSerializableStream since this is supposedly necessary for serializing embedded objects):

case class Dependency(var id: String, var specifier: String) extends OSerializableStream {
  def this() = this(null, null)

  override def toStream: Array[Byte] = {
    val bytes: Array[Byte] = Json.prettyPrint(Json.toJson(this)).getBytes
    bytes
  }

  override def fromStream(iStream: Array[Byte]): OSerializableStream = {
    val json = Json.parse(iStream)
    val dependency = Json.fromJson[Dependency](json).get
    dependency
  }
}

object Dependency {
  implicit val versionFormat = Json.format[Dependency]
}

What am I doing wrong here?

Answer 1

Embedded objects must be of the ODocument type, it doesn't help to make Dependency implement OSerializable. The following code shows how:

val myHashSet = new java.util.HashSet[ODocument]()
myHashSet.add(new ODocument("Dependency").field("id", "mydep").field("specifier", "1.0"))
val myVersion = new ODocument("Version")
  .field("id", "myversion")
  .field("dependencies", myHashSet)
myVersion.save()