org.datanucleus.api.jpa

Class NucleusJPAHelper

java.lang.Object

org.datanucleus.api.jpa.NucleusJPAHelper

public class NucleusJPAHelper
extends Object

Helper for persistence operations with JPA.

Constructor Summary

Constructors

Constructor and Description
NucleusJPAHelper()

Method Summary

Modifier and Type	Method and Description
static Object	getDatastoreIdForEntity(Object obj) Convenience method to allow access to the datastore id of an object when it is using DN Extension "datastore-id".
static Object[]	getDetachedStateForObject(Object obj) Accessor for the jdoDetachedState field of a detached object.
static String[]	getDirtyFields(Object obj, javax.persistence.EntityManager em) Accessor for the names of the dirty fields of the persistable object.
static javax.persistence.EntityManager	getEntityManager(Object obj) Accessor for the EntityManager for the supplied (persistable) object.
static javax.persistence.PersistenceException	getJPAExceptionForNucleusException(org.datanucleus.exceptions.NucleusException ne) Convenience method to convert a Nucleus exception into a JPA exception.
static String[]	getLoadedFields(Object obj, javax.persistence.EntityManager em) Accessor for the names of the loaded fields of the persistable object.
static Object	getObjectId(Object obj)
static String	getObjectState(Object obj) Convenience method to return a string of the state of an object.
static Object	getSurrogateVersionForEntity(Object obj) Convenience method to allow access to the version of an object when it is using DN Extension "surrogate-version".
static boolean	isDeleted(Object obj) Convenience accessor for whether the object is deleted.
static boolean	isDetached(Object obj) Convenience accessor for whether the object is detached.
static boolean	isPersistent(Object obj) Convenience accessor for whether the object is persistent.
static boolean	isTransactional(Object obj) Convenience accessor for whether the object is transactional.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NucleusJPAHelper

public NucleusJPAHelper()

Method Detail

getSurrogateVersionForEntity

public static Object getSurrogateVersionForEntity(Object obj)

Convenience method to allow access to the version of an object when it is using DN Extension "surrogate-version".

Parameters:

obj - The entity object

Returns:

The (surrogate) version

getDatastoreIdForEntity

public static Object getDatastoreIdForEntity(Object obj)

Convenience method to allow access to the datastore id of an object when it is using DN Extension "datastore-id".

Parameters:

obj - The entity object

Returns:

The datastore id key

getObjectId

public static Object getObjectId(Object obj)

getEntityManager

public static javax.persistence.EntityManager getEntityManager(Object obj)

Accessor for the EntityManager for the supplied (persistable) object. If the object is detached or transient then returns null.

Parameters:

obj - The persistable object

Returns:

The entity manager for this object

isPersistent

public static boolean isPersistent(Object obj)

Convenience accessor for whether the object is persistent.

Parameters:

obj - The object

Returns:

Whether it is persistent

isDeleted

public static boolean isDeleted(Object obj)

Convenience accessor for whether the object is deleted.

Parameters:

obj - The object

Returns:

Whether it is deleted

isDetached

public static boolean isDetached(Object obj)

Convenience accessor for whether the object is detached.

Parameters:

obj - The object

Returns:

Whether it is persistent

isTransactional

public static boolean isTransactional(Object obj)

Convenience accessor for whether the object is transactional.

Parameters:

obj - The object

Returns:

Whether it is transactional

getObjectState

public static String getObjectState(Object obj)

Convenience method to return a string of the state of an object. Will return things like "detached", "persistent", etc

Parameters:

obj - The object

Returns:

The state

getDetachedStateForObject

public static Object[] getDetachedStateForObject(Object obj)

Accessor for the jdoDetachedState field of a detached object. The returned array is made up of :

• 0 - the identity of the object
• 1 - the version of the object (upon detach)
• 2 - loadedFields BitSet
• 3 - dirtyFields BitSet

Parameters:

obj - The detached object

Returns:

The detached state

getDirtyFields

public static String[] getDirtyFields(Object obj,
                                      javax.persistence.EntityManager em)

Accessor for the names of the dirty fields of the persistable object.

Parameters:

obj - The persistable object

em - The Entity Manager (only required if the object is detached)

Returns:

Names of the dirty fields

getLoadedFields

public static String[] getLoadedFields(Object obj,
                                       javax.persistence.EntityManager em)

Accessor for the names of the loaded fields of the persistable object.

Parameters:

obj - Persistable object

em - The Entity Manager (only required if the object is detached)

Returns:

Names of the loaded fields

getJPAExceptionForNucleusException

public static javax.persistence.PersistenceException getJPAExceptionForNucleusException(org.datanucleus.exceptions.NucleusException ne)

Convenience method to convert a Nucleus exception into a JPA exception. If the incoming exception has a "failed object" then create the new exception with a failed object. Otherwise if the incoming exception has nested exceptions then create this exception with those nested exceptions. Else create this exception with the incoming exception as its nested exception.

Parameters:

ne - NucleusException

Returns:

The JPAException