@DomainService

The @DomainService annotation indicates that the (concrete) class should be automatically instantiated as a domain service.

@Inherited
@Target({
        ElementType.TYPE,
        ElementType.ANNOTATION_TYPE
})
@Retention(RetentionPolicy.RUNTIME)
@Service @Singleton
public @interface DomainService {

    NatureOfService nature()                    (1)
            default NatureOfService.VIEW;

    String objectType()                         (2)
            default "";

}
1 nature()

Whether the actions of this domain service should be rendered in UI menus only, or the RestfulObjects REST API only, or both

2 objectType()

Equivalent to @DomainObject#objectType(), specifies the objectType of the service.

The instanceId for services is always "1".

For example:

@DomainService(
    nature=NatureOfService.DOMAIN,
    repositoryFor=Loan.class
)
public class LoanRepository {
    @Programmatic
    public List<Loan> findLoansFor(Borrower borrower) { /* ... */ }
}

nature()

This is the purpose of the nature attribute: to indicates the intent of (all of) the actions defined within the domain service.

The values of the enum are:

  • VIEW

    The default; the service’s actions appear on menu bars, can be contributed, appear in the REST API

  • REST

    The service’s actions are intended only to be listed in the REST API exposed by the RestfulObjects viewer.

The actual class name of the domain service is only rendered for the VIEW natures.

For other services (whose actions should not be part of the metamodel and should not appear in the UI), just use Spring’s @Service, @Repository or @Component annotations.

Another example:

@Repository
public class LoanRepository {
    public List<Loan> findLoansFor(Borrower borrower) {
        // ...
    }
}

A final example:

@DomainService( nature=NatureOfService.VIEW )
@RequiredArgsConstructor(onConstructor_ = {@Inject} )
public class Loans {                                   (1)

    @Inject
    private final LoanRepository loanRepository;       (2)

    @Action(semantics=SemanticsOf.SAFE)
    public List<Loan> findOverdueLoans() {
        // ...
    }
}
1 name is intended to be rendered in the UI
2 it’s common for domain-layer domain services to be injected into presentation layer services.

objectType()

The objectType attribute is used to provide a unique alias for the domain service’s class name.

This value is used internally to generate a string representation of an service identity (the Oid). This can appear in several contexts, including:

Example

For example:

@DomainService(
    objectType="orders.OrderMenu"
)
public class OrderMenu {
    ...
}

Precedence

The rules of precedence are:

  1. @DomainService#objectType

  2. getId()

  3. The fully qualified class name.

This might be obvious, but to make explicit: we recommend that you always specify an object type for your domain services.

Otherwise, if you refactor your code (change class name or move package), then any externally held references to the OID of the service will break. At best this will require a data migration in the database; at worst it could cause external clients accessing data through the Restful Objects viewer to break.

If the object type is not unique across all domain classes then the framework will fail-fast and fail to boot. An error message will be printed in the log to help you determine which classes have duplicate object tyoes.