I posted this question on SO
<https://stackoverflow.com/questions/52913897/combine-jackson-mixing-with-valueinstantiator>,
but it didn't get much attention, so I'm posting here as well.
-----
I'd like to deserialize the following class:
case class Target(
a: Option[Long],
b: String
)
while providing a custom initial value for missing fields.
I'm using this mixin to overcome this bug:
https://github.com/FasterXML/jackson-module-scala/wiki/FAQ#deserializing-optionint-and-other-primitive-challenges
trait Mixin {
@JsonDeserialize(contentAs = classOf[Long]) def a: Option[Long]}
and I'm using this ValueInstantiator to provide a custom initial value:
class TargetInstantiator extends ValueInstantiator{
override def canCreateUsingDefault: Boolean = true
override def createUsingDefault(ctxt: DeserializationContext): AnyRef = {
Target(Some(1), "bbb")
}}
the mixing and the instantiator work well on their own, but when I combine
the 2 together, the mixin doesn't seem to have any effect
here is the full code:
case class Target(
a: Option[Long],
b: String
)trait Mixin {
@JsonDeserialize(contentAs = classOf[Long]) def a: Option[Long]}
class TargetInstantiator extends ValueInstantiator{
override def canCreateUsingDefault: Boolean = true
override def createUsingDefault(ctxt: DeserializationContext): AnyRef = {
Target(Some(1), "bbb")
}}
val svi = new SimpleValueInstantiators()
svi.addValueInstantiator(classOf[Target], new TargetInstantiator)
val module = new SimpleModule("MyModule")
module.setValueInstantiators(svi)
val mapper = new ObjectMapper()
.registerModule(DefaultScalaModule)
.registerModule(module)
.addMixIn(classOf[Target], classOf[Mixin])val req =
"""{
| "a": 123
|}
""".stripMarginval res = mapper.readValue(req, classOf[Target])
println(res.a.map(_ + 1)) //should print Some(124)
println(res.b) //should print "bbb"
the above code would fail with the error
java.lang.Integer cannot be cast to java.lang.Long
on the first print.
if I comment out .registerModule(module), and add "b" to the json string,
the code would work.
Is it possible to make the mixin and the instantiator work together?
--
You received this message because you are subscribed to the Google Groups
"jackson-user" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
For more options, visit https://groups.google.com/d/optout.
