Aws-sdk-java-v2: DynamoDB enhanced client Mappers - annotations can be used only on methods

[yairzaslavsky]

DynamoDB ehnchant client mappers annotations can be applied only to methods, not to fields.
This make it hard (or event create) data classes in Kotlin which are perfect to represent DDB model classes.

Describe the bug

I'm working on a Kotlin project using DDB enhanced client mappers.
When we worked with v1 we could have created model classes like this:
https://gist.github.com/yairzaslavsky/486a66871c57bf23629a812320abf697

But now, that we want to use the enhanced client , we cannot create data classes, as we the annotations can be applied only to methods.
This ended up with us creating code like this:
https://gist.github.com/yairzaslavsky/8cc4e87ff83425b492522d2bcdb70f04

Expected Behavior

I would expect to have the ability to implement a data class like in the first link.

Current Behavior

At the moment i cannot implement a data class this way, as i have to override the getter behavior

Steps to Reproduce

You can use the above links as example

Possible Solution

Change the annotations to to be applied to fields as well.

Context

I am developing a server side component using Kotlin that uses DDB.

Your Environment

• AWS Java SDK version used:
  v2 (kotlin 1.3-x)
• JDK version used:
  8
• Operating System and version:
  Linux

[debora-ito]

Hi @yairzaslavsky thank you for your interest in the DynamoDB Enhanced Client.

We understand the issue but applying annotations in the methods is by design. I'm changing this to a feature request to support Kotlin specific implementations.

If anyone wants to show support for this feature please thumbs up 👍 the original post to help us with prioritization.

[yairzaslavsky]

Thank you Deborah.

[drissamri]

Glad I found this issue, new to Kotlin and didn't understand why it wasn't working, nothing specific was pointing me to the dynamodb annotations

[yairzaslavsky]

@drissamri i saw you thumbed up, you are supposed to thumb up the original post. Thanks for showing interest in this.

[cchu-tr]

@yairzaslavsky
can't you do this?

@DynamoDbBean
data class Person(
    @get:DynamoDbPartitionKey
    var personId: String,

    @get:DynamoDbAttribute(value = "name")
    var name: String,

    @get:DynamoDbSecondaryPartitionKey(indexNames = ["familyName-index"])
    var familyName: String,

    @get:DynamoDbAttribute(value = "createTime")
    var createTime: Long = java.time.Instant.now().epochSecond,

    @get:DynamoDbAttribute(value = "updateTime")
    var updateTime: Long = java.time.Instant.now().epochSecond
)

?

[Zomis]

This is related to, or possible duplicate of, #2096