如何配置EclipseLink HistoryPolicy以跟蹤對GlassFish 4中JPA實體的Element Collection屬性所做的更改？

Question

我在Person實體上成功配置了EclipseLink HistoryPolicy，並驗證在GlassFish 4上運行的EclipseLink跟蹤PERSON_VERSION表中PERSON表的更改。然後我伸出了地圖屬性我一個人實體持有人的電話號碼作爲顯示在下面的類：

@Customizer(PersonCustomizer.class) 
public class Person { 
    @ID 
    private Long id; 
    @Version 
    private Integer version; 
    .... 
    @ElementCollection 
    @MapKeyEnumerated(EnumType.STRING) 
    private Map<TelephoneNumberType, String> telephoneNumber; 
    ... 
} 

然後我試圖擴大我DescriptorCustomizer類跟蹤更改PERSON_TELEPHONENUMBER表作爲展現在以下課程：

public class PersonCustomizer implements DescriptorCustomizer { 
    public void customize(ClassDescriptor descriptor) throws Exception { 
     HistoryPolicy policy = new HistoryPolicy(); 
     policy.addStartFieldName("VALIDFROM"); 
     policy.addEndFieldName("VALIDTO"); 
     policy.setShouldHandleWrites(true); 
     policy.addHistoryTableName("PERSON", "PERSON_VERSION"); 
     descriptor.setHistoryPolicy(policy); 

     DirectMapMapping mapping = (DirectMapMapping) descriptor.getMappingForAttributeName("telephoneNumber"); 
     HistoryPolicy policy2 = new HistoryPolicy(); 
     policy2.setShouldHandleWrites(true); 
     policy2.addHistoryTableName("PERSON_TELEPHONENUMBER", "PERSON_VERSION_TELEPHONENUMBER"); 
     mapping.setHistoryPolicy(policy2); 
    } 
} 

不幸的是，GlassFish拒絕部署我的應用程序。如果我註釋掉上述PersonCustomizer類中的mapping.setHistoryPolicy（policy2）行，應用程序將部署，但PERSON_TELEPHONENUMBER表的更改不會在PERSON_VERSION_TELEPHONENUMBER表中跟蹤。

以下是GlassFish應用部署過程中報告該錯誤消息的示例：

Local Exception Stack: 
Exception [EclipseLink-0] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.IntegrityException 
Descriptor Exceptions: 
--------------------------------------------------------- 

Exception [EclipseLink-41] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.DescriptorException 
Exception Description: A non-read-only mapping must be defined for the sequence number field. 
Descriptor: RelationalDescriptor(Person --> [DatabaseTable(PERSON)]) 

Runtime Exceptions: 
--------------------------------------------------------- 

java.lang.NullPointerException 

    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.initializeDescriptors(DatabaseSessionImpl.java:689) 
    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.initializeDescriptors(DatabaseSessionImpl.java:625) 
    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.initializeDescriptors(DatabaseSessionImpl.java:565) 
    at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.postConnectDatasource(DatabaseSessionImpl.java:792) 

... 

Descriptor Exceptions: 
--------------------------------------------------------- 

Local Exception Stack: 
Exception [EclipseLink-41] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.DescriptorException 
Exception Description: A non-read-only mapping must be defined for the sequence number field. 
Descriptor: RelationalDescriptor(Person --> [DatabaseTable(PERSON)]) 
    at org.eclipse.persistence.exceptions.DescriptorException.mappingForSequenceNumberField(DescriptorException.java:929) 
    at org.eclipse.persistence.internal.descriptors.ObjectBuilder.validate(ObjectBuilder.java:4090) 
    at org.eclipse.persistence.descriptors.ClassDescriptor.selfValidationAfterInitialization(ClassDescriptor.java:4061) 
    at org.eclipse.persistence.descriptors.ClassDescriptor.validateAfterInitialization(ClassDescriptor.java:5910) 

... 

Runtime Exceptions: 
--------------------------------------------------------- 


java.lang.NullPointerException 
    at org.eclipse.persistence.history.HistoryPolicy.initialize(HistoryPolicy.java:320) 
    at org.eclipse.persistence.mappings.DirectCollectionMapping.initialize(DirectCollectionMapping.java:1457) 
    at org.eclipse.persistence.mappings.DirectMapMapping.initialize(DirectMapMapping.java:367) 
    at org.eclipse.persistence.descriptors.ClassDescriptor.initialize(ClassDescriptor.java:2980) 

... 

謝謝你的幫助。

Answer 1

這是可能的ManyToManyMapping：

orm.xml中

<entity class="xxx.Client"> 
    <customizer class="xxx.ClientCustomizer"/> 
... 
      <many-to-many name="segments"> 
       <cascade> 
        <cascade-all/> 
       </cascade> 
       <join-table name="CLIENT_SEGMENTS"> 
        <join-column name="CLIENTID" referenced-column-name="ID"/> 
        <inverse-join-column name="SEGMENTID" referenced-column-name="ID" /> 
       </join-table> 
      </many-to-many> 

    ... 
    </entity> 

public class Client 
    implements Serializable 
{ 
... 
     protected List<Segment> segments; 
} 
public class Segment 
    implements Serializable 
{ 

    @NotNull 
    protected int id; 
    protected String name; 
    protected String description; 
    protected String rule; 
    ... 
} 

public class ClientCustomizer implements DescriptorCustomizer { 

    @Override 
    public void customize(ClassDescriptor descriptor) throws Exception { 
     ManyToManyMapping mapping = (ManyToManyMapping) descriptor.getMappingForAttributeName("segments"); 
     HistoryPolicy policy = new HistoryPolicy(); 
     policy.addStartFieldName("ROW_START"); 
     policy.addEndFieldName("ROW_END"); 

     policy.addHistoryTableName("CLIENT_SEGMENTS", "CLIENT_SEGMENTS_HIST"); 
     mapping.setHistoryPolicy(policy); 
    } 

} 

又見http://www.eclipse.org/forums/index.php/t/457024/