Interface StateInterrogation
A call to JDOHelper to get the status of an instance is handled internally if the parameter instance implements PersistenceCapable. For non-binary-compatible implementations, there is no requirement that persistent instances implement PersistenceCapable. Therefore, if the parameter does not implement PersistenceCapable, JDOHelper delegates to all registered instances of StateInterrogation until an instance can handle the request.
For JDOHelper isXXX methods, which return boolean, the
corresponding method in StateInterrogation returns Boolean. If the
return value is null
then the StateInterrogation does
not recognize the parameter as being handled by it. A non-null return
value indicates that the implementation has determined the answer.
For JDOHelper getXXX methods, which return an Object, each registered StateInterrogation is given the parameter until one of them returns a non-null value, which is passed to the caller.
For JDOHelper makeDirty, each
registered StateInterrogation is given the parameter until one of
them returns true, indicating that it has handled the call.
An instance that implements this interface must be registered with the
JDOImplHelper
.
- Since:
- 2.0
- Version:
- 2.0
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Method Summary
Modifier and TypeMethodDescriptiongetObjectId
(Object pc) Return a copy of the JDO identity associated with the parameter instance.Return the associatedPersistenceManager
if there is one.Return a copy of the JDO identity associated with the parameter instance.getVersion
(Object pc) Return the version of the parameter instance.Tests whether the parameter instance has been deleted.isDetached
(Object pc) Tests whether the parameter instance is detached.Tests whether the parameter instance is dirty.Tests whether the parameter instance has been newly made persistent.isPersistent
(Object pc) Tests whether the parameter instance is persistent.Tests whether the parameter instance is transactional.boolean
Explicitly mark the parameter instance and field dirty.
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Method Details
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isPersistent
Tests whether the parameter instance is persistent. Instances that represent persistent objects in the data store returnBoolean.TRUE
.Instances known by the implementation to be non-persistent return
Boolean.FALSE
.Instances not recognized by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
Boolean.TRUE
if the parameter instance is persistent.- See Also:
-
isTransactional
Tests whether the parameter instance is transactional. Instances whose state is associated with the current transaction returnBoolean.TRUE
.Instances known by the implementation to be non-transactional return
Boolean.FALSE
.Instances not recognized by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
Boolean.TRUE
if the parameter instance is transactional.- See Also:
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isDirty
Tests whether the parameter instance is dirty. Instances that have been modified, deleted, newly made persistent in the current transaction, or modified while detached returnBoolean.TRUE
.Instances known by the implementation to be non-dirty return
Boolean.FALSE
.Instances not recognized by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
Boolean.TRUE
if the parameter instance has been modified in the current transaction, or while detached.- See Also:
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isNew
Tests whether the parameter instance has been newly made persistent. Instances that have been made persistent in the current transaction returnBoolean.TRUE
.Instances known by the implementation to be non-new return
Boolean.FALSE
.Instances not recognized by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
Boolean.TRUE
if the parameter instance was made persistent in the current transaction.- See Also:
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isDeleted
Tests whether the parameter instance has been deleted. Instances that have been deleted in the current transaction returnBoolean.TRUE
.Instances known by the implementation to be non-deleted return
Boolean.FALSE
.Instances not recognized by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
Boolean.TRUE
if the parameter instance was deleted in the current transaction.- See Also:
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isDetached
Tests whether the parameter instance is detached. Instances that are detached returnBoolean.TRUE
.Instances known by the implementation to be non-detached return
Boolean.FALSE
.Instances not recognized by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
Boolean.TRUE
if the parameter instance is detached.- See Also:
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getPersistenceManager
Return the associatedPersistenceManager
if there is one. Transactional and persistent instances return the associatedPersistenceManager
.Transient non-transactional instances return
null
.Instances unknown by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
- the
PersistenceManager
associated with the parameter instance. - See Also:
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getObjectId
Return a copy of the JDO identity associated with the parameter instance.Persistent instances of
PersistenceCapable
classes have a JDO identity managed by thePersistenceManager
. This method returns a copy of the ObjectId that represents the JDO identity.Instances unknown by the implementation return
null
.The ObjectId may be serialized and later restored, and used with a
PersistenceManager
from the same JDO implementation to locate a persistent instance with the same data store identity.If the JDO identity is managed by the application, then the ObjectId may be used with a
PersistenceManager
from any JDO implementation that supports thePersistenceCapable
class.If the JDO identity is not managed by the application or the data store, then the ObjectId returned is only valid within the current transaction.
- Parameters:
pc
- the instance.- Returns:
- a copy of the ObjectId of the parameter instance as of the beginning of the transaction.
- See Also:
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getTransactionalObjectId
Return a copy of the JDO identity associated with the parameter instance.Instances unknown by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
- a copy of the ObjectId of the parameter instance as modified in this transaction.
- See Also:
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getVersion
Return the version of the parameter instance.Instances unknown by the implementation return
null
.- Parameters:
pc
- the instance.- Returns:
- a copy of the ObjectId of the parameter instance as modified in this transaction.
- See Also:
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makeDirty
Explicitly mark the parameter instance and field dirty. Normally,PersistenceCapable
classes are able to detect changes made to their fields. However, if a reference to an array is given to a method outside the class, and the array is modified, then the persistent instance is not aware of the change. This API allows the application to notify the instance that a change was made to a field.Instances unknown by the implementation are unaffected.
- Parameters:
pc
- the instance.fieldName
- the name of the field to be marked dirty.- Returns:
- Whether it was made dirty
- See Also:
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