Modeling weak entities with a composite key and @ManyToOne

[Florian Kroiß]

Hi,

I'm trying to model a simple scenario with a strong entity (House) and weak entity (Room)

The primary key of the house is an id, the primary key of the room is a composite key consisting of the house id and room no.

I tried to model this with the following 3 classes:

@Entity

public class House extends Model implements Serializable {

  private static final long serialVersionUID = 1L;

  @Id

  @GeneratedValue

  private String id;

  @PrivateOwned

  @OneToMany(cascade = CascadeType.ALL, mappedBy = "id.house")

  private List<Room> rooms;

  //Getter + Setter

}

@Entity

public class Room extends Model implements Serializable {

  private static final long serialVersionUID = 1L;

  @EmbeddedId

  private RoomPK id;

  //Getter + Setter

  

}

@Embeddable

public class RoomPK implements Serializable {

  

  private static final long serialVersionUID = 1L;

  @ManyToOne

  @JoinColumn(name = "id")

  private House house;

  @Size(max = 32)

  @Column(insertable = false, nullable = false)

  private String roomNo;

  //Getter + Setter + hashCode + equals

  

}

I created a small test within our ebean fork here (https://github.com/FOCONIS/ebean/commit/3b477ed957952c753afd56785884bd51e954f6e3)

Is this the correct way to implement this? Because ebean currently throws the following error:

java.lang.ExceptionInInitializerError: null

at io.ebean.BaseTestCase.<clinit>(BaseTestCase.java:72)

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:423)

at org.junit.runners.BlockJUnit4ClassRunner.createTest(BlockJUnit4ClassRunner.java:217)

at org.junit.runners.BlockJUnit4ClassRunner$1.runReflectiveCall(BlockJUnit4ClassRunner.java:266)

at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)

at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:263)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)

at io.ebean.ConditionalTestRunner.runChild(ConditionalTestRunner.java:33)

at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)

at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)

at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)

at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)

at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)

at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)

at org.junit.runners.ParentRunner.run(ParentRunner.java:363)

at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)

at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)

Caused by: java.lang.RuntimeException: java.lang.RuntimeException: Error reading annotations for org.tests.compositekeys.db.RoomPK

at io.ebean.Ebean$ServerManager.<init>(Ebean.java:89)

at io.ebean.Ebean$ServerManager.<init>(Ebean.java:67)

at io.ebean.Ebean.<clinit>(Ebean.java:43)

... 24 common frames omitted

Caused by: java.lang.RuntimeException: Error reading annotations for org.tests.compositekeys.db.RoomPK

at io.ebeaninternal.server.deploy.parse.ReadAnnotations.readAssociations(ReadAnnotations.java:60)

at io.ebeaninternal.server.deploy.BeanDescriptorManager.readDeployAssociations(BeanDescriptorManager.java:1422)

at io.ebeaninternal.server.deploy.BeanDescriptorManager.registerEmbeddedBean(BeanDescriptorManager.java:757)

at io.ebeaninternal.server.deploy.BeanDescriptorManager.readEntityDeploymentInitial(BeanDescriptorManager.java:747)

at io.ebeaninternal.server.deploy.BeanDescriptorManager.deploy(BeanDescriptorManager.java:375)

at io.ebeaninternal.server.core.InternalConfiguration.<init>(InternalConfiguration.java:202)

at io.ebeaninternal.server.core.DefaultContainer.createServer(DefaultContainer.java:138)

at io.ebeaninternal.server.core.DefaultContainer.createServer(DefaultContainer.java:70)

at io.ebeaninternal.server.core.DefaultContainer.createServer(DefaultContainer.java:1)

at io.ebean.EbeanServerFactory.create(EbeanServerFactory.java:58)

at io.ebean.Ebean$ServerManager.getWithCreate(Ebean.java:126)

at io.ebean.Ebean$ServerManager.<init>(Ebean.java:75)

... 26 common frames omitted

Caused by: io.ebean.config.BeanNotRegisteredException: Error with association to [class org.tests.compositekeys.db.House] from [org.tests.compositekeys.db.RoomPK.house]. Is class org.tests.compositekeys.db.House registered? Does it have the @Entity annotation? See https://ebean.io/docs/trouble-shooting#not-registered

at io.ebeaninternal.server.deploy.parse.AnnotationAssocOnes.beanTable(AnnotationAssocOnes.java:202)

at io.ebeaninternal.server.deploy.parse.AnnotationAssocOnes.readManyToOne(AnnotationAssocOnes.java:213)

at io.ebeaninternal.server.deploy.parse.AnnotationAssocOnes.readAssocOne(AnnotationAssocOnes.java:66)

at io.ebeaninternal.server.deploy.parse.AnnotationAssocOnes.parse(AnnotationAssocOnes.java:57)

at io.ebeaninternal.server.deploy.parse.ReadAnnotations.readAssociations(ReadAnnotations.java:49)

... 37 common frames omitted

Has anyone build a similar scenario or are there better ways to implement this?

Thanks and best regards

Florian

[Rob Bygrave]

Well the cause error says "BeanNotRegisteredException: Error with association to [class org.tests.compositekeys.db.House] from [org.tests.compositekeys.db.RoomPK.house]. Is class org.tests.compositekeys.db.House registered?"

So that is the first question you need to answer.

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