Update dynamodb attribute with long data type using dynamodb mapper

Question

I have a Java POJO for writing into dynamodb. The DynamoDB is being updated by 2 different AWS lambdas from 2 different AWS SQS. I am using dynamoDBMapper to save record into dynamodb. The mapper config looks like below

DynamoDBMapperConfig mapperConfig = DynamoDBMapperConfig.Builder().withSaveBehavior(DynamoDBMapperConfig.SaveBehavior.UPDATE_SKIP_NULL_ATTRIBUTES)
                .build();

I am using UPDATE_SKIP_NULL_ATTRIBUTES so that I don't have to provide all attributes while saving a record and the save() will not overwrite the existing record.

My POJO looks like

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder(toBuilder = true)
@DynamoDBTable(tableName = "OrderShipment")
public class Order {
    @DynamoDBHashKey(attributeName = "id")
    @NonNull
    public String id;
    @DynamoDBRangeKey(attributeName = "sortKey")
    @NonNull
    public String sortKey;
    @DynamoDBAttribute(attributeName = "createdDate")
    public long createdDate;
    @DynamoDBAttribute(attributeName = "lastUpdated")
    public long lastUpdated;
    @DynamoDBAttribute(attributeName = "status")
    public String status;

I am writing createdDate from one lambda and lastUpdated,status from second lambda using dynamodbMapper's save() API. To my surprise, the status field is not being overwritten, however createdDate and lastUpdated are being overwritten from the events and being set to 0. From my understanding UPDATE_SKIP_NULL_ATTRIBUTES should update the record and not overwrite the existing attributes in the record and it's working expected for status, but not for the long type. Am I missing something here?

score 0 · Answer 1 · answered Feb 24 '23 at 21:01

I did a silly mistake in Order POJO class. Instead of Long, I used the primitive data type long, which can not be null and hence it was initialized with 0 every time. I changed the data type for createdDate and lastUpdated to Long, it's working as expected.

Update dynamodb attribute with long data type using dynamodb mapper

1 Answers1