Fetch original state of the object

[Gaurav Malhotra]

Hi,

  I want to write attribute change validation rules. I gathered that eclipse link automatically weave change tracker into the jpa entities + it uses AttributeChangeTrackingPolicy (by default), hence keep the clone of the original object.
Pre - condition :- Weaving should be enabled.
   (Please validate my understanding)

  How can I get the original state of the object. By original state I mean state of object before the update chnages were applied.

  AttributeChangeListner acl = (  AttributeChangeListner) (((ChanageTracker) xxxx)._persistence_getPropertyChangeListener())

  Now how to get the original state of the object???

Regards,
Gaurav Malhotra

[James Sutherland]

Attribute change tracking does not keep the original state, only the list of attributes that change.  When using weaving attribute change tracking is the default, otherwise it is deferred.

If you use deferred change tracking, then you can get the backupClone from the UnitOfWork, it will have the original values.

I think there is an enhancement request for have the ObjectChangeSets contain the old values, feel free to vote for this, or add one if you can't find it.  You may also be able to create your own AttributeChangeTrackingPolicy subclass that keeps the old values.

Gaurav Malhotra wrote:

Hi,

  I want to write attribute change validation rules. I gathered that eclipse link automatically weave change tracker into the jpa entities + it uses AttributeChangeTrackingPolicy (by default), hence keep the clone of the original object.
Pre - condition :- Weaving should be enabled.
   (Please validate my understanding)

  How can I get the original state of the object. By original state I mean state of object before the update chnages were applied.

  AttributeChangeListner acl = (  AttributeChangeListner) (((ChanageTracker) xxxx)._persistence_getPropertyChangeListener())

  Now how to get the original state of the object???

Regards,
Gaurav Malhotra

[Gaurav Malhotra]

Hi James,

   I was on holiday so couldn't look into your reply.

   Creating MyAttributeChangeListner (extending AttributeChangeListner) I was able to hold onto the old values.
  Few more questions

  1) How can I tell eclipselink to start weaving MyAttributeChangeListner into the jpa entities rather than default AttributeChangeListner.

 2) How can I get the new jpa entities from the unit of work (RepeatbleUnitOfWork)? (in insert/update use cases)

Reason for above questions
  I an constructing annotation driven validation framework for eclipselink for my project. My validation are fired from the aspect which can weaved around the crud service and validation parsing info is constructed at deployment time. The validation framework exploits apache common bean validations + valang + spring validation framework + groovy script (or any pluggable script like MVEL)
Note :- no proxy is created around the JPA entities.
Examples
// Spring validators
@OhiBusinessRule(name = "Relation Validations", beforeInsUpdValidators = {
                GenericDynamicFieldsValidator.class, RelationValidator.class })

// valang
@OhiBusinessRule(name = "valangRules",
                     rulesBefore = { "dynamicFieldUsage.fieldUsageName : upper(?) = TRUE: 'dynamicFieldUsage.fieldUsageName is not in upper case' : 'errors.dfusFieldUsageName'",
                                     "dynamicFieldUsage.inLov : ? = TRUE : 'Indication lov is not True' : 'errors.indInLov'" },
                     valangFunctions = { Upper.class })

//  groovy
@OhiBusinessRule(name = "groovyRules",
                     rulesBefore = { "relation.name != null: 'relation name cannot be null' : 'errors.relation.name'})


   

Regards,
Gaurav Malhotra
Oracle

Gaurav Malhotra wrote:

Hi,

  I want to write attribute change validation rules. I gathered that eclipse link automatically weave change tracker into the jpa entities + it uses AttributeChangeTrackingPolicy (by default), hence keep the clone of the original object.
Pre - condition :- Weaving should be enabled.
   (Please validate my understanding)

  How can I get the original state of the object. By original state I mean state of object before the update chnages were applied.

  AttributeChangeListner acl = (  AttributeChangeListner) (((ChanageTracker) xxxx)._persistence_getPropertyChangeListener())

  Now how to get the original state of the object???

Regards,
Gaurav Malhotra

[tware]

Hi Gaurav,

   The best way to enable your MyAttributeChangeListner is to write a subclass
of
org.eclipse.persistence.descriptors.changetracking.AttributeChangeTrackingPolicy
and enable it on your descriptors either through a SessionCustomizer or a
DescriptorCustomizer.

   You should be able to simply override the setChangeListener(Object clone,
UnitOfWorkImpl uow, ClassDescriptor descriptor) method and maybe the
setAggregateChangeListener(Object parent, Object aggregate, UnitOfWorkImpl uow,
ClassDescriptor descriptor, String mappingAttribute) method depending on what
you want to track.

   The UnitOfWork tracks new objects in a number of lists.  Try taking a look at
the newObjectsCloneToOriginal list.

-Tom

Gaurav Malhotra wrote:

> Hi James,
>
>    I was on holiday so couldn't look into your reply.
>
>    Creating MyAttributeChangeListner (extending AttributeChangeListner) I
> was able to hold onto the old values.
>   Few more questions
>
>   1) How can I tell eclipselink to start weaving MyAttributeChangeListner
> into the jpa entities rather than default AttributeChangeListner.
>
>  2) How can I get the new jpa entities from the unit of work
> (RepeatbleUnitOfWork)? (in insert/update use cases)
>
> Reason for above questions
>   I an constructing annotation driven validation framework for eclipselink
> for my project. My validation are fired from the aspect which can weaved
> around the crud service and validation parsing info is constructed at
> deployment time. The validation framework exploits apache common bean
> validations + valang + spring validation framework + groovy script (or any
> pluggable script like MVEL)
> Note :- no proxy is created around the JPA entities.
> Examples
> // Spring validators
> @OhiBusinessRule(name = "Relation Validations", beforeInsUpdValidators = {
> GenericDynamicFieldsValidator.class, RelationValidator.class })
>
> // valang
> @OhiBusinessRule(name = "valangRules",
>                      rulesBefore = { "dynamicFieldUsage.fieldUsageName :
> upper(?) = TRUE: 'dynamicFieldUsage.fieldUsageName is not in upper case' :
> 'errors.dfusFieldUsageName'",
>                                      "dynamicFieldUsage.inLov : ? = TRUE :
> 'Indication lov is not True' : 'errors.indInLov'" },
>                      valangFunctions = { Upper.class })
>
> //  groovy
> @OhiBusinessRule(name = "groovyRules",
>                      rulesBefore = { "relation.name != null: 'relation name
> cannot be null' : 'errors.relation.name'})
>
>
>    
>
> Regards,
> Gaurav Malhotra
> Oracle
>
>
> Gaurav Malhotra wrote:
>> Hi,
>>
>>   I want to write attribute change validation rules. I gathered that
>> eclipse link automatically weave change tracker into the jpa entities + it
>> uses AttributeChangeTrackingPolicy (by default), hence keep the clone of
>> the original object.
>> Pre - condition :- Weaving should be enabled.
>>    (Please validate my understanding)
>>
>>   How can I get the original state of the object. By original state I mean
>> state of object before the update chnages were applied.
>>
>>   AttributeChangeListner acl = (  AttributeChangeListner)
>> (((ChanageTracker) xxxx)._persistence_getPropertyChangeListener())
>>
>>   Now how to get the original state of the object???
>>
>> Regards,
>> Gaurav Malhotra
>>
>

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