ResponseTypes.multipleInstancesOf() type mismatch

Axon Framework
1

I have a simple rest endpoint that looks like:

    @GetMapping("/products/admin")
    fun getProductsAdmin(
        @RequestParam(required = false) state: ProductState = ProductState.PENDING)
    : CompletableFuture<List<ProductAdminView>> {
        return queryGateway.query(GetProducts(state),
            ResponseTypes.multipleInstancesOf(ProductAdminView::class.java))
    }

The query handler looks like:

  @QueryHandler
    fun handle(query: GetProducts): List<ProductAdminView> {
        return productRepository.findByState(query.state)
            .map { productDocument ->
                ProductAdminView(
                    id = productDocument.id,
                    name = productDocument.name,
                    description = productDocument.description,
                    price = productDocument.price,
                    inStock = productDocument.inStock,
                    imageUrl = productDocument.imageUrl,
                    state = productDocument.state
                )
            }
    }

This unfortunately results in an exception:

java.lang.IllegalArgumentException: Retrieved response [class java.util.ArrayList] is not convertible to a List of the expected response type [class dev.fidil.monostore.product.ProductAdminView]
	at org.axonframework.messaging.responsetypes.MultipleInstancesResponseType.convert(MultipleInstancesResponseType.java:180) ~[axon-messaging-4.9.2.jar:4.9.2]
	at org.axonframework.messaging.responsetypes.MultipleInstancesResponseType.convert(MultipleInstancesResponseType.java:47) ~[axon-messaging-4.9.2.jar:4.9.2]
	at org.axonframework.messaging.responsetypes.ConvertingResponseMessage.getPayload(ConvertingResponseMessage.java:102) ~[axon-messaging-4.9.2.jar:4.9.2]
	at org.axonframework.queryhandling.DefaultQueryGateway.lambda$query$2(DefaultQueryGateway.java:97) ~[axon-messaging-4.9.2.jar:4.9.2]
	at java.base/java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718) ~[na:na]
	at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:510) ~[na:na]
	at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2147) ~[na:na]
	at org.axonframework.axonserver.connector.query.AxonServerQueryBus$ResponseProcessingTask.lambda$run$0(AxonServerQueryBus.java:905) ~[axon-server-connector-4.9.2.jar:4.9.2]
	at org.axonframework.tracing.Span.run(Span.java:101) ~[axon-messaging-4.9.2.jar:4.9.2]
	at org.axonframework.axonserver.connector.query.AxonServerQueryBus$ResponseProcessingTask.run(AxonServerQueryBus.java:904) ~[axon-server-connector-4.9.2.jar:4.9.2]
	at org.axonframework.axonserver.connector.PriorityRunnable.run(PriorityRunnable.java:58) ~[axon-server-connector-4.9.2.jar:4.9.2]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[na:na]
	at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]

I feel like I’m missing something simple but I cannot see it. It seems like the query handler might be wrapping an extra list around its response somehow. Any help much appreciated.

I am using Axon Framework 4.9.3 with mongodb as read store.

2

Assuming you use use Jackson for serialisation the query messages and responses, you need something like:

@Bean
@Primary
fun serializer(objectMapper: ObjectMapper): Serializer {
    return JacksonSerializer.builder()
            .objectMapper(objectMapper.copy())
            .defaultTyping()
            .lenientDeserialization()
            .build()
}

For the primary serializer used. Jackson will not add typing info by default, and therefore, it can’t deserialize the elements of the list.

3

Thanks for the reply!

Adding the suggested serializer bean produces an exception:

Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `org.axonframework.eventhandling.tokenstore.ConfigToken` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('org.axonframework.eventhandling.tokenstore.ConfigToken')
 at [Source: (byte[])"["org.axonframework.eventhandling.tokenstore.ConfigToken",{"config":["java.util.Collections$SingletonMap",{"id":"acdb5308-8814-41e7-b850-6b5957cc9222"}]}]"; line: 1, column: 2]
	at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:63) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1739) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1364) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.std.StdDeserializer._deserializeFromString(StdDeserializer.java:311) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromString(BeanDeserializerBase.java:1514) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:197) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:187) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeFromArray(BeanDeserializer.java:647) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther(BeanDeserializer.java:211) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:187) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.ObjectReader._bindAndClose(ObjectReader.java:2105) ~[jackson-databind-2.15.4.jar:2.15.4]
	at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:1583) ~[jackson-databind-2.15.4.jar:2.15.4]
	at org.axonframework.serialization.json.JacksonSerializer.deserialize(JacksonSerializer.java:205) ~[axon-messaging-4.9.3.jar:4.9.3]
	... 50 common frames omitted
4

Did you maybe make changes to the Mongo Token store configuration? It seems like the token was stored with a serializer with default typing, but now default typing is disabled.

5

I didn’t make any changes to the mongo token store, but it definitely didn’t like the new jackson configuration until I deleted the mongo token store. It worked great once I did. Thanks again!

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