Mahdi Mahdi - 1 year ago 86
Scala Question

Does salat support de/serialization of type Either in scala?

I have the following case classes:

case class DataEntity
name: String,
value: Either[Complex, String]
case class Complex (x: String, y: String)

As far as I can see, serialization (writing to MongoDB) goes fine, but it fails in deserializing:


argument type mismatch

$anon$2(class catalog.DataEntity @$$anon$1@3fa48431) toObject failed on:
SYM: catalog.DataEntity
public catalog.DataEntity(java.lang.String,scala.util.Either<catalog.Complex, java.lang.String>)

---------- CONSTRUCTOR EXPECTS FOR PARAM [0] --------------
NAME: name
TYPE: java.lang.String
DEFAULT ARG [Missing, but unnecessary because input value was supplied]
@Ignore false
---------- CONSTRUCTOR INPUT ------------------------
TYPE: java.lang.String

---------- CONSTRUCTOR EXPECTS FOR PARAM [1] --------------
NAME: value
TYPE: scala.util.Either<catalog.Complex, java.lang.String>
DEFAULT ARG [Missing, but unnecessary because input value was supplied]
@Ignore false
---------- CONSTRUCTOR INPUT ------------------------
TYPE: com.mongodb.BasicDBList
[ [ "File" , "/bin/ls" ...

The output above is manually matched to the simplified case classes above.
I am using salatDAO for reading and writing to DB.

Answer Source

Either is not currently supported. I've updated the "Supported Types" wiki accordingly.

Note that in Salat 1.10.0-SNAPSHOT, you will get an error like the following (when attempting to deserialize from JSON strings):

scala> SalatExamples.eitherHolder()
serialized EitherHolder(Left(data)) to { "_typeHint" : "com.novus.salat.examples.EitherHolder" , "either" : [ "data"]} for storage in mongo

com.novus.salat.json.UnsupportedJsonTransformationException: serialize: Unsupported JSON transformation for class='scala.util.Left', value='Left(data)'

NOTE: salat has certain limitations. It cannot deserialize JSON into case classes having fields such as:
- Arrays such as Array[String]
- Nested collections such as Map[String, List[String]]
- Optional collections such as Option[List[String]]

For more information, please visit:

See also:

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