AWS DynamoDB Enhanced Client provides the AutoGeneratedUuidExtension and automatically generates a UUID during putItem operation. If using it as partition key, the newly created value needs to be retrieved otherwise a retrieval is not possible with getItem.

@DynamoDbBean
public class Example {

    private String uuid;

    @DynamoDbPartitionKey
    @DynamoDbAutoGeneratedUuid
    public String getUuid() {
        return uuid;
    }

    public void setUuid(String uuid) {
        this.uuid = uuid;
    }
}

The putItem method does not update the value of the bean:

@Test
void newOfferShouldHaveUuidGenerated() {
    Example example = new Example();
    table.putItem(example); // putItem is void
    assertThat(example.getUuid()).isNotNull();
}

AWS DynamoDB Enhanced Client provides the AutoGeneratedUuidExtension and automatically generates a UUID during putItem operation. If using it as partition key, the newly created value needs to be retrieved otherwise a retrieval is not possible with getItem.

@DynamoDbBean
public class Example {

    private String uuid;

    @DynamoDbPartitionKey
    @DynamoDbAutoGeneratedUuid
    public String getUuid() {
        return uuid;
    }

    public void setUuid(String uuid) {
        this.uuid = uuid;
    }
}

The putItem method does not update the value of the bean:

@Test
void newOfferShouldHaveUuidGenerated() {
    Example example = new Example();
    table.putItem(example); // putItem is void
    assertThat(example.getUuid()).isNotNull();
}

• amazon-web-services
• amazon-dynamodb
• dynamodb-enhanced-client

2 Answers 2

EnhancedClient uses a beforeWrite hook and does not bind to the object. My recommendation here is to auto generate your own UUID which you can manually set to your object instead of relying on the auto generated one.

Use DynamoDbTable::updateItem

Maybe not a good practice, but based on the documentation you can use updateItem instead of putItem:

Updates an item in the mapped table, or adds it if it doesn't exist. This operation calls the low-level DynamoDB API UpdateItem operation.

Example response = table.updateItem(example);

This return the generated uuid by the annotation @DynamoDbAutoGeneratedUuid, I already test it and it works.