org.seedstack.business.api.interfaces.query.finder

Annotation Type Finder

@Retention(value=RUNTIME)
@Target(value=TYPE)
public @interface Finder

This annotation is the interface marker for a Finder in SEED.

A Finder is a CQRS (Command Query Responsibility Segregation) concept that focus on "Read" part of the architecture. It will return DTO or Representation of Entities.

Main reasons are scalability and coupling decrease. Be sure to follow CAST Training : "Business Framework".

How it works ?

1) First, create an interface annotated.

 @Finder
 public interface FooFinder {
     List<FooDto> findFoosWithName(String name);
 }
 

2) Then, create the implementation of this interface.

 @Finder
 public class JpaFooFinder implements FooFinder {

    @Inject
    EntityManager entityManager;

    List<FooDto> findFoosWithName(String name) {
         entityManager.createQuery( ... ) ;
         return query.getResultList();
    }
 

3) Finally, SEED will automatically provide the injection of the Interface

 @Inject
 private FooFinder fooFinder;

 - - - - 8< - - - -

 @Inject
 public void provideFinder (FooFinder fooFinder)

 - - - - 8< - - - -

 fooFinder.findFoosWithName(nameToFind);
 

Author:

epo.jemba@ext.mpsa.com