org.seedstack.business

Annotation Type Service

@Documented
 @Retention(value=RUNTIME)
 @Target(value={TYPE,ANNOTATION_TYPE})
public @interface Service

A service is a stateless object that implements domain, applicative, infrastructure or interface logic.

This annotation can be applied to an interface to declare a service. Any class implementing the annotated interface will be registered by the framework as an implementation of this service.

Considering the following service:

  @Service
  public interface MoneyTransferService {
     void transfer(Account source, Account target);
  }
 

Its implementation is declared as:

  public class ElectronicMoneyTransferService implements MoneyTransferService {
      public void transfer(Account source, Account target) {
          // implementation
      }
  }
 

The implementation can then be injected as follows:

 public class SomeClass {
      @Inject
      MoneyTransferService moneyTransferService;
 }
 

When a service interface has multiple implementations, it is necessary to differentiate them by using a different javax.inject.Qualifier annotation on each. This qualifier can then be used at the injection point to specify which implementation is required. Considering the additional implementation of the MoneyTransferService below:

  @Named("solidGold")
  public class SolidGoldMoneyTransferService implements MoneyTransferService {
      public void transfer(Account source, Account target) {
          // implementation
      }
  }
 

This implementation can be injected as follows:

  public class SomeClass {
       @Inject
       @Named("solidGold")
       TransferService transferService;
  }