org.seedstack.business.spi

Annotation Type GenericImplementation

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

This annotation can be used on an implementation of a Repository or an Assembler to declare it as a generic implementation.

Generic implementations are able to work with all types satisfying the conditions of their interface. For instance a generic implementation of a Repository must be able to work with any aggregate in the system.

A generic implementation often exist along with user-defined explicit implementations of the same interface, so it is recommended to annotate it with a javax.inject.Qualifier, leaving the unqualified implementation for user code. A generic implementation is instantiated through assisted injection, invoking a constructor whose unique parameter must be an array of the classes it will work on. Consider the following example:

  @GenericImplementation
  @SomeQualifier
  public class SomeGenericRepository<A extends AggregateRoot<ID>, ID> implements
 Repository<A, ID> {
       @Inject
       public SomeGenericRepository( @Assisted Object[] genericClasses) {
           // genericClasses contains the aggregate root class and the identifier class
           // this instance must work with
       }
  }
 

This generic implementation can be injected as follows:

 public class SomeClass {
      @Inject
      @SomeQualifier
      private Repository<SomeAggregate, SomeId> someAggregateRepository;
 }