Inheritance with deserialisation

[tagy]

I'm wondering if there is a nice way to deal with inheritance when deserialising. Not sure if I have missed something here or not.

The following is 2 classes that are mostly the same but each have one unique property. This deserialises correctly.

val dogXML ="""
    <dog id="111">
    <age>12</age>
      <title>
        <text locale="en-GB"><![CDATA[dog_title_en_gb]]></text>
        <text locale="en-GB"><![CDATA[dog_title_fr_fr]]></text>
      </title>
      <bark>dog_test</bark>
    </dog>
""".trimIndent()

val catXML ="""
    <dog id="222">
    <age>8</age>
      <title>
        <text locale="en-GB"><![CDATA[cat_title_en_gb]]></text>
        <text locale="en-GB"><![CDATA[cat_title_fr_fr]]></text>
      </title>
      <meow>cat_test</meow>
    </dog>
""".trimIndent()

@Serializable
class Dog(
    val id: String,

    @XmlElement(true)
    val age: Int,

    @XmlSerialName(value = "title")
    @XmlChildrenName(value = "text")
    val titles: List<LocalisedTitle>,

    @XmlElement(true)
    val bark: String,
)

@Serializable
class Cat(
    val id: String,

    @XmlElement(true)
    val age: Int,

    @XmlSerialName(value = "title")
    @XmlChildrenName(value = "text")
    val titles: List<LocalisedTitle>,

    @XmlElement(true)
    val meow: String,
)

@Serializable
class LocalisedTitle(
    @XmlElement(false) val locale:String,
    @XmlValue(true) val value: String
)

If you want to move the common properties to a base type, I'm not sure if there is a neat way to do that?

The following works, but now the properties in the base type must have default values, which is not ideal.

@Serializable
open class Animal(

    val id: String? = null,

    @XmlElement(true)
    val age: Int = 0,

    @XmlSerialName(value = "title")
    @XmlChildrenName(value = "text")
    val titles: List<LocalisedTitle> = emptyList(),
)

@Serializable
class Dog(

    @XmlElement(true)
    val bark: String

): Animal()

@Serializable
class Cat(

    @XmlElement(true)
    val meow: String

): Animal()

@Serializable
class LocalisedTitle(
    @XmlElement(false) val locale:String,
    @XmlValue(true) val value: String
)

[pdvrieze]

The way to do this is for the base class to not have a primary constructor at all (that way the serialization plugin can generate a constructor for its own use).