Can we create an aggregateIdentifer inside aggregate and setting the identifier as aggregateType+UUID.randomUUID.tostring()?

Axon Framework
1

@Entity
@Table(name = “rewards”)
@Aggregate(snapshotTriggerDefinition = “snapshotTriggerDefinition”)
@Data
@Slf4j
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class RewardAggregate{

@Id
@AggregateIdentifier
private String rewardId;
private String name;
private String description;

} This is my aggregate currently, but while setting the primary key i want to set it as Type of the aggregate concated with a randomUUID.
Ex: RewardAggregate||550e8400-e29b-41d4-a716-446655440000 this as identifier. Also i want to create it using an abstract class, where i should be using it for all of my classes

2

Hi Prasanna,

It’s fine to have the aggregate identifier be a composite as you mention; typically though, the UUID itself is sufficient.

4

Hi @Marc_Klefter,

I’m able to create a composite aggregate identifier when instantiating a new aggregate. However, when attempting to update the existing instance, it fails to retrieve it properly, resulting in an AggregateNotFoundException.
Could you help me resolve this issue?

5

Are you providing the full String representation of the composite identifer - e.g. “RewardAggregate||550e8400-e29b-41d4-a716-446655440000” - in the @TargetAggregateIdentifier in your command?

6

Yeah I provided it as TargetAggregateidentifer @Marc_Klefter

7

Can you provide the code for the command, aggregate and the sending of the command?

8

This is my baseAggregate
@Getter
public abstract class BaseAggregate {

@AggregateIdentifier
public String getAggregateIdentifier() {
    return generateAggregateIdentifier();
}

protected String generateAggregateIdentifier() {
    return this.getClass().getSimpleName() + "||" + getIdentifier();
}

protected abstract String getIdentifier();

}
@Entity
@Table(name = “rewards”)
@Aggregate(snapshotTriggerDefinition = “snapshotTriggerDefinition”)
@Data
@NoArgsConstructor
@AllArgsConstructor
public class RewardAggregate extends BaseAggregate {

@Id
private String rewardId;
private String name;
private String description;
private String criteriaExpression;
private double points;
private Instant createdAt;
private Instant updatedAt;
private UUID updatedBy;
private UUID serviceId;
private String serviceName;
private String status; //TODO:

@OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name = "reward_id")
@AggregateMember
private List<RewardCriteria> rewardCriteria = new ArrayList<>();

@Override
protected String getIdentifier(){
    return rewardId+"||"+serviceId;
}

CommandHandler
public RewardAggregate(CreateRewardCommand command) {
// super(command.getServiceId());

    log.debug("Handling CreateRewardCommand for rewardId: {} with command:{}", this.getRewardId(), command);

// if (command.getRewardId() == null || command.getRewardId().isEmpty()) {
// throw new ServiceCommandException(“Reward ID cannot be null or empty.”, 400);
// }
this.rewardId= UUID.randomUUID().toString();
this.serviceId= command.getServiceId();
try {

        RewardCreatedEvent rewardCreatedEvent = RewardCreatedEvent.builder()
                .rewardId(UUID.randomUUID().toString()) // Use generated ID
                .name(command.getName())
                .description(command.getDescription())
                .criteriaExpression(command.getCriteriaExpression())
                .points(command.getPoints())
                .createdAt(Instant.now())
                .updatedAt(Instant.now())
                .serviceId(command.getServiceId())
                .serviceName(command.getServiceName())
                .updatedBy(command.getUpdatedBy())
                .status("ACTIVE")
                .build();

}
This is my aggregate
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class CreateRewardCommand {

private String name;
private String description;
private String criteriaExpression;
private double points;
private UUID updatedBy;
private UUID serviceId;
private String serviceName;

}
This is my createCommand where it doesn’t contains @TargetAggregateIdentifer since it is to create a new instance.
@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class UpdateRewardCommand {
@TargetAggregateIdentifier
private String rewardId;
private double rewardPoints;
private String criteriaExpression;
private UUID updatedBy;
}
This is my updateRewardCommand

9

@Marc_Klefter The issue I encountered is in the code above.

10

There’s a little bit to untangle here:

  • The (composite) aggregate identifier for your RewardAggregate has the form RewardAggregate||<rewardId>||<serviceId>. But your UpdateRewardCommand has a @TargetAggregateIdentifier of only rewardId. Thus, the identifiers do not match.

  • In the RewardAggregate, it seems you’re generating a UUID for the rewardId and assigning it in the command handler. Then, you’re creating a RewardCreatedEvent and again generating a UUID for the event’s rewardId field.

    Don’t set aggregate state in command handlers - rather set the rewardId in the @EventSourcingHandler for the RewardCreatedEvent.