org.eiichiro.acidhouse

Annotation Type Referential

@Documented
@Target(value=FIELD)
@Retention(value=RUNTIME)
public @interface Referential

Referential is a marker annotation to represent the annotated field is referential property (References the "Master" entity as read-only). Like this:

 @Entity
 public class Entity7 {
 
        @Key String id;
 
        int i;
 
        @Referential Entity1 entity1;
 
 }
 
 ...
 Entity1 entity1 = new Entity1();
 entity1.id = "Reference1";
 entity1.i = 1;
 Entity7 entity71 = new Entity7();
 entity71.id = "Key71";
 entity71.i = 71;
 entity71.entity1 = entity1;
 Entity7 entity72 = new Entity7();
 entity72.id = "Key72";
 entity72.i = 72;
 entity72.entity1 = entity1;
 
 Session session = new AppEngineDatastoreSession();
 Transaction transaction = session.beginTransaction();
 
 try {
        session.put(entity1);
        session.put(entity71);
        session.put(entity72);
        transaction.commit();
 } catch (Exception e) {
        transaction.rollback();
        throw e;
 }
 
 transaction = session.beginTransaction();
 
 try {
        entity1 = session.get(Entity1.class, "Reference1");
        entity1.i = 11;         // from 1 to 11.
        session.update(entity1);
        transaction.commit();
 } catch (Exception e) {
        transaction.commit();
        throw e;
 } finally {
        session.close();
 }
 
 session = new AppEngineDatastoreSession();
 entity71 = session.get(Entity7.class, "Key71");
 entity72 = session.get(Entity7.class, "Key72");
 assertThat(entity71.entity1.i, is(11));
 assertThat(entity72.entity1.i, is(11));
 

Author:

Eiichiro Uchiumi