Any values when use @Polymorphic

[auzatsepin]

I have test to parse as following:

import kotlinx.serialization.Polymorphic
import kotlinx.serialization.SerialName
import kotlinx.serialization.Serializable
import kotlinx.serialization.builtins.serializer
import kotlinx.serialization.modules.SerializersModule
import kotlinx.serialization.modules.polymorphic
import kotlinx.serialization.serializer
import nl.adaptivity.xmlutil.serialization.XML
import nl.adaptivity.xmlutil.serialization.XmlElement
import nl.adaptivity.xmlutil.serialization.XmlSerialName
import nl.adaptivity.xmlutil.serialization.XmlValue

private val module = SerializersModule {
    polymorphic(Any::class) {
        subclass(Order1::class, serializer())
        subclass(StopOrder1::class, serializer())
        subclass(String::class, String.serializer())
    }
}

private val parser = XML(module) {
    autoPolymorphic = true
}

interface XmlEntity

@Serializable
data class Orders1(@XmlValue var orders: List<@Polymorphic Any>) : XmlEntity

@Serializable
@XmlSerialName("order")
data class Order1(
    @SerialName("transactionid") val transactionId: String,
    @XmlElement @SerialName("secid") val secId: String,
) : XmlEntity

@Serializable
@XmlSerialName("stoporder")
data class StopOrder1(
    @SerialName("transactionid") val transactionId: String,
    @XmlElement @SerialName("secid") val secId: String,
) : XmlEntity

@Serializable
@SerialName("stoploss")
data class StopLoss(
    @SerialName("usecredit") val useCredit: String,
    @XmlElement @SerialName("activationprice") val activationPrice: Double,
    @XmlElement val quantity: Int,
    @XmlElement @SerialName("bymarket") val byMarket: Boolean
) : XmlEntity

val xml = """<orders>
    <order transactionid="32021651">
        <secid>8135</secid>
    </order>
    <stoporder transactionid="20105503">
        <secid>8135</secid>
    </stoporder>
    <stoporder transactionid="31465073">
        <secid>8135</secid>
    </stoporder>
</orders>"""

fun main() {
    val decoded = parser.decodeFromString(serializer<Orders1>(), xml)
    println("size " + decoded.orders.size)
    println(decoded)
}

It deserializes correctly, but extra string elements are added to the result, such as empty lines with carriage returns.

size 7
Orders1(orders=[
    , Order1(transactionId=32021651, secId=8135), 
    , StopOrder1(transactionId=20105503, secId=8135), 
    , StopOrder1(transactionId=31465073, secId=8135), 
])

simple and working option to filter by interface, but maybe there is a more correct way ?

[pdvrieze]

In this case you don't want to use @XmlValue for Orders.

To explain a bit, what @XmlValue does is that it ensures that unexpected content is picked up. That includes text. Alternatively you could use @XmlIgnoreWhitespace on the orders attribute to make it ignore whitespace text (but happily include other non-whitespace text).

[pdvrieze]

Important here is that the xml library actually uses the module to find all candidate types that can be in the orders list, so it will find all children in the module based on tag name. For @XmlValue strings are special cased in that they don't need a tag wrapper.

[auzatsepin]

thanks with @XmlIgnoreWhitespace works great.

[pdvrieze]

@auzatsepin Note that for this case the best approach is to not use @XmlValue. As an aside the @XmlValue case also has a cache key issue if the same list is also used in the same format instance without the value (fixed in the dev branch) - only relevant for string elements (in case they are in a list in an xmlValue they are captured by in place strings, without the value annotation they are wrapped in a <xsd:string> element..