Implement domain service

• For each service there will be an abstract class Service Base generated in the SDK.

• The Service Base provides access to the repository, the entity builder, the event builder and the event producer.

• The Service Base contains one abstract method named execute.

• This execute method needs to be implemented in the generated implementation file for the service.

• Service execute method will take a modelled Input Entity as a parameter.

• Service execute method will return a modelled Output Entity as a return type.

• If a service is modelled with Business Errors, it will be added as throws declaration to service execute method.

• If a service is modelled with Events, for each event there will be an inherited method in the Service Base class that takes the event as an input and publishes it.

• It is also possible to publish events directly using EventProducerService.

Example of Balance service implementation file.

//... imports
import myproj.sdk.domain.schemas.SchemaGroup.BalanceCheckedSchema;

@Service
public class BalanceService extends BalanceServiceBase {

	private static Logger log = LoggerFactory.getLogger(BalanceService.class);
	
	public BalanceService(DomainEntityBuilder entityBuilder, DomainEventBuilder eventBuilder, EventProducerService eventProducer, Repository repo) {
		super(entityBuilder, eventBuilder, eventProducer, repo);
	}

    // Example of a service implementation logic
	@NewSpan
	@Override
	public Balance execute(CreditCard creditCard) throws CreditCardNotFoundError {

		log.info("BalanceService.execute()");
  
        // Use repository to get card instance
		Optional<Card> cardRootEntity = this.repo.getCc().getCard().findById(creditCard.getId());
		if(cardRootEntity.isPresent()) {

		  // Use Domain Entity Builder from base class to create an instance of Balance entity
		  Balance balance = this.entityBuilder.getCc().getBalance().build();
		  balance.setAvaliableBalance(cardRootEntity.getBalance());
		  balance.setHoldAmount(cardRootEntity.getHoldAmount());

		  // Publish event, if the event is using a schema from the schema registry as payload
		  BalanceCheckedEvent schemaEvent = this.eventBuilder.getCc().getBalanceCheckedEvent().build();

		  // Create the payload
		  BalanceCheckedSchema schema = new BalanceCheckedSchema();
		  schema.setProperty1('value');
		  schemaEvent.setPayload(schema);

		  // Publish the event
		  this.publishBalanceCheckedEvent(schemaEvent);

		  /**
			* Create an event and set payload entity, if the event is using an entity as payload
			* only available for event support 1.0
			* @deprecated use schemas from the schema registry instead
			*/
		  BalanceUpdatedEvent entityEvent = this.eventBuilder.getCc().getBalanceUpdatedEvent().build();
		  // Using an entity as event payload
		  entityEvent.setPayload(balance);
		  // Publish the event
		  this.publishBalanceUpdatedEvent(entityEvent);

		  return balance;

		} else {
			String errorMessage = String.format("Credit card with id %s not found", creditCard.getId());
           throw new CreditCardNotFoundError(errorMessage);
		}
	}

Course Implement Domain Logic