Event bus codec doesn't work for a list of objet

[ZouhairBear]

Context

I have used this exemple CustomMessageCodec to make a codec for a simple object. It works for a simple object so I wanted to use for a list of objects. This didn't work.

Exemple of used Codec class

import fr.convergence.proddoc.common.model.surcharge.SurchargeDocument
import fr.convergence.proddoc.common.util.json
import io.vertx.core.buffer.Buffer
import io.vertx.core.eventbus.MessageCodec
import io.vertx.mutiny.core.Vertx
import kotlinx.serialization.builtins.ListSerializer
import javax.inject.Inject
import javax.inject.Singleton

@Singleton
class SurchargeDocumentListCodecRegistering {
    @Inject
    constructor(vertx: Vertx) {
        vertx.eventBus().registerCodec(SurchargeDocumentListCodec())
    }
}

class SurchargeDocumentListCodec : MessageCodec<List<SurchargeDocument>, List<SurchargeDocument>> {

    override fun encodeToWire(buffer: Buffer, list: List<SurchargeDocument>) {

        val encodedList = json.encodeToString(ListSerializer(SurchargeDocument.serializer()), list)
        val length = encodedList.toByteArray().size
        buffer.appendInt(length)
        buffer.appendString(encodedList)
    }

    override fun decodeFromWire(position: Int, buffer: Buffer): List<SurchargeDocument> {
        var _pos = position
        val length = buffer.getInt(_pos)
        val jsonContent = buffer.getString(4.let { _pos += it; _pos }, length.let { _pos += it; _pos })
        return json.decodeFromString(ListSerializer(SurchargeDocument.serializer()), jsonContent)
    }

    override fun transform(list: List<SurchargeDocument>): List<SurchargeDocument> {
        return list.toList() // Transform as needed
    }

    override fun name(): String {
        return this.javaClass.simpleName
    }

    override fun systemCodecID(): Byte {
        return -1
    }
}

Extra

• OS : ubuntu 22.04
• JAVA version : 17

[tsegismont]

This will not work because Vert.x has no way to know if the list object was templated.

If your objects are all annotated with Jackson databind annotations, you could use a default codec selector: https://vertx.io/blog/whats-new-in-vert-x-4-3/#dynamic-codec-lookup