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Posted to dev@openjpa.apache.org by Michael Dick <mi...@gmail.com> on 2011/03/23 14:22:31 UTC
Re: OpenJPA Date Proxy serialization problem when using entities with GWT
I haven't had a chance to look at your example application, but I think we
need to make some changes to the way we handle proxies.
Currently there's no way to prevent proxies from being inserted. It's not
intuitive when they will be inserted, and they can be tough to remove. What
I'd propose is to make it work something like this :
if openjpa.ProxyManager.TrackChanges == False :
# No proxies are inserted. Ever.
else :
if openjpa.DetachState.DetachedStateField == "true":
# proxies are inserted when the entity is flushed (or committed)
# proxies are not removed when the entity is detached
# proxies are not removed when the entity is serialized
elif openjpa.DetachState.DetachedStateField == "transient" :
# proxies are inserted when the entity is flushed (or committed)
# proxies are not removed when the entity is detached
# proxies are removed when the entity is serialized
elif openjpa.DetachState.DetachedStateField == "false" :
# proxies are inserted when the entity is flushed (or committed)
# proxies are removed when the entity is detached
# proxies are removed when the entity is serialized
>From what I've seen none of these are accurate for trunk, and the related
code path is a bit tangled (or I just haven't groked it).
For your specific use case, would you want the proxies to ever be inserted?
-mike
On Sat, Mar 19, 2011 at 7:27 AM, Prashant Bhat <pr...@gmail.com>wrote:
> Hi,
>
> I've created a sample project to explore this issue. Please see the
> attached sample project.
>
> To run this test, execute this maven command: mvn compile openjpa:enhance
> gwt:compile test
>
> The GWT compiler takes long time to compile. Once it is complete, this will
> start a jetty server and opens URL http://localhost:8080/ in the default
> browser. Now click on the 'Save Sales Orders' which fails with the following
> exception.
>
> com.google.gwt.user.client.rpc.SerializationException: Type
> 'org.apache.openjpa.util.java$util$Date$proxy'
>
> I really appreciate your help in solving this or any suggestion to use
> alternate approach, Thanks.
>
> Regards,
> Prashant
>
> On Thu, Mar 10, 2011 at 11:26 PM, Michael Dick <mi...@gmail.com>wrote:
>
>> Hi Prashant,
>>
>> I've been looking into the Date proxies recently. What I've found is that
>> the proxies are removed if you serialize the entity or use detachCopy()
>> (in
>> this case the original entity retains the proxies and the new copy does
>> not
>> have them). I'm looking into a better solution for this use case, but the
>> detachment code is pretty tangled, and it might take a little while to
>> work
>> out a safe option.
>>
>> I'm not sure why using a DTO didn't work for you. How did you copy the
>> date
>> field from your entity?
>>
>> -mike
>>
>> On Wed, Mar 9, 2011 at 9:13 PM, Prashant Bhat <pr...@gmail.com>
>> wrote:
>>
>> > Hi All,
>> >
>> > We're developing an application using OpenJpa 2.1, Spring-3.0.5 and
>> > GWT-2.2.0. This integration works for all other types in the entity, but
>> > fails for fields of type Date with the following exception:
>> > --
>> > com.google.gwt.user.client.rpc.SerializationException: Type
>> > 'org.apache.openjpa.util.java$util$Date$proxy' was not included in the
>> set
>> > of types which can be serialized by this SerializationPolicy or its
>> Class
>> > object could not be loaded. For security purposes, this type will not be
>> > serialized.: instance = Sat Dec 31 00:00:00 SGT 2011
>> > --
>> > I tried using DTO instead of using an entity directly, but when date
>> > property is copied from Entity object to DTO, the same proxy will be
>> set.
>> > So
>> > it doesn't work either.
>> >
>> > When searched, I found lot of references to detaching the entity to
>> remove
>> > all proxies needed by Jpa. It works, but this needs to be explicitly
>> > called,
>> > while the same works without calling this, in our Swing app which gets
>> the
>> > serialized objects through Spring Remoting. And also, as there're a lot
>> of
>> > DAOs already written, this is going to be major change.
>> >
>> > So, is there a openjpa configuration setting to use, so that all proxies
>> > are
>> > removed on em.close() ? I really appreciate any help to solve this.
>> >
>> > Thanks,
>> > Prashant
>> >
>>
>
>
Re: OpenJPA Date Proxy serialization problem when using entities with GWT
Posted by Prashant Bhat <pr...@gmail.com>.
Hi,
I've a worked around this problem with small changes to Proxy creation for
Date Java types. I'm not familiar with OpenJPA codebase, so my workaround is
not configurable as you've described above. It just doesn't proxy date
objects, so I'm not sending the changes patch. But I think, it'll be very
useful for any GWT based projects, using entities directly on client side,
if this is implemented in the core. Thanks.
Regards,
Prashant
On Thu, Mar 24, 2011 at 10:28 PM, Michael Dick <mi...@gmail.com>wrote:
> I agree.
>
> What I'm aiming to do here is to give the application the option to remove
> both the StateManager and proxies at a point that makes sense for their
> application. For a lot of them removing the StateManager and proxies at
> detach time will make sense. There's no way to do that right now though.
>
> To answer Rick's question, the proxies delegate back to the StateManager to
> dirty a field. If there's no SM they don't do anything, otherwise it's up to
> the StateManager.
>
> -mike
>
>
>
Re: OpenJPA Date Proxy serialization problem when using entities with GWT
Posted by Michael Dick <mi...@gmail.com>.
I agree.
What I'm aiming to do here is to give the application the option to remove
both the StateManager and proxies at a point that makes sense for their
application. For a lot of them removing the StateManager and proxies at
detach time will make sense. There's no way to do that right now though.
To answer Rick's question, the proxies delegate back to the StateManager to
dirty a field. If there's no SM they don't do anything, otherwise it's up to
the StateManager.
-mike
On Wed, Mar 23, 2011 at 8:57 PM, Prashant Bhat <pr...@gmail.com>wrote:
> I don't know much about the benefits of using proxies, but in our
> particular usage, all proxies should be removed when the entity is
> detached/serialized. Then we can use entities directly in GWT avoiding DTOs
> and also with this, client side will not have dependency on OpenJPA at
> runtime.
>
> Regards,
> Prashant
>
>
> On Wed, Mar 23, 2011 at 9:22 PM, Michael Dick <mi...@gmail.com>wrote:
>
>> I haven't had a chance to look at your example application, but I think we
>> need to make some changes to the way we handle proxies.
>>
>> Currently there's no way to prevent proxies from being inserted. It's not
>> intuitive when they will be inserted, and they can be tough to remove.
>> What
>> I'd propose is to make it work something like this :
>>
>> if openjpa.ProxyManager.TrackChanges == False :
>> # No proxies are inserted. Ever.
>>
>> else :
>>
>> if openjpa.DetachState.DetachedStateField == "true":
>> # proxies are inserted when the entity is flushed (or committed)
>> # proxies are not removed when the entity is detached
>> # proxies are not removed when the entity is serialized
>>
>> elif openjpa.DetachState.DetachedStateField == "transient" :
>> # proxies are inserted when the entity is flushed (or committed)
>> # proxies are not removed when the entity is detached
>> # proxies are removed when the entity is serialized
>>
>> elif openjpa.DetachState.DetachedStateField == "false" :
>> # proxies are inserted when the entity is flushed (or committed)
>> # proxies are removed when the entity is detached
>> # proxies are removed when the entity is serialized
>>
>> From what I've seen none of these are accurate for trunk, and the related
>> code path is a bit tangled (or I just haven't groked it).
>>
>> For your specific use case, would you want the proxies to ever be
>> inserted?
>>
>> -mike
>>
>>
>
Re: OpenJPA Date Proxy serialization problem when using entities with GWT
Posted by Prashant Bhat <pr...@gmail.com>.
Hi Pinaki,
The opentrader domain entities do not use j.u.Date fields. But as in the
above provided sample application, GWT serialization exception is thrown if
the entity being serialized has a Date field.
Regards,
Prashant
On Thu, Mar 24, 2011 at 9:18 PM, Pinaki Poddar <pp...@apache.org> wrote:
> Hi Prashant,
> You may like to check out a complete GWT + OpenJPA sample in
> openjpa-examples/opentrader directory.
>
>
>
> -----
> Pinaki
> --
> View this message in context:
> http://openjpa.208410.n2.nabble.com/OpenJPA-Date-Proxy-serialization-problem-when-using-entities-with-GWT-tp6156425p6204055.html
> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>
Re: OpenJPA Date Proxy serialization problem when using entities
with GWT
Posted by Pinaki Poddar <pp...@apache.org>.
Hi Prashant,
You may like to check out a complete GWT + OpenJPA sample in
openjpa-examples/opentrader directory.
-----
Pinaki
--
View this message in context: http://openjpa.208410.n2.nabble.com/OpenJPA-Date-Proxy-serialization-problem-when-using-entities-with-GWT-tp6156425p6204055.html
Sent from the OpenJPA Users mailing list archive at Nabble.com.
Re: OpenJPA Date Proxy serialization problem when using entities with GWT
Posted by Prashant Bhat <pr...@gmail.com>.
I don't know much about the benefits of using proxies, but in our
particular usage, all proxies should be removed when the entity is
detached/serialized. Then we can use entities directly in GWT avoiding DTOs
and also with this, client side will not have dependency on OpenJPA at
runtime.
Regards,
Prashant
On Wed, Mar 23, 2011 at 9:22 PM, Michael Dick <mi...@gmail.com>wrote:
> I haven't had a chance to look at your example application, but I think we
> need to make some changes to the way we handle proxies.
>
> Currently there's no way to prevent proxies from being inserted. It's not
> intuitive when they will be inserted, and they can be tough to remove. What
> I'd propose is to make it work something like this :
>
> if openjpa.ProxyManager.TrackChanges == False :
> # No proxies are inserted. Ever.
>
> else :
>
> if openjpa.DetachState.DetachedStateField == "true":
> # proxies are inserted when the entity is flushed (or committed)
> # proxies are not removed when the entity is detached
> # proxies are not removed when the entity is serialized
>
> elif openjpa.DetachState.DetachedStateField == "transient" :
> # proxies are inserted when the entity is flushed (or committed)
> # proxies are not removed when the entity is detached
> # proxies are removed when the entity is serialized
>
> elif openjpa.DetachState.DetachedStateField == "false" :
> # proxies are inserted when the entity is flushed (or committed)
> # proxies are removed when the entity is detached
> # proxies are removed when the entity is serialized
>
> From what I've seen none of these are accurate for trunk, and the related
> code path is a bit tangled (or I just haven't groked it).
>
> For your specific use case, would you want the proxies to ever be inserted?
>
> -mike
>
>
Re: OpenJPA Date Proxy serialization problem when using entities with GWT
Posted by Rick Curtis <cu...@gmail.com>.
> # proxies are not removed when the entity is detached
Do proxies 'do' anything when an entity is detached? If no, I vote get rid
of them. Other than that thought, I vote pull the trigger.
Thanks,
Rick
Re: OpenJPA Date Proxy serialization problem when using entities with GWT
Posted by Prashant Bhat <pr...@gmail.com>.
I don't know much about the benefits of using proxies, but in our
particular usage, all proxies should be removed when the entity is
detached/serialized. Then we can use entities directly in GWT avoiding DTOs
and also with this, client side will not have dependency on OpenJPA at
runtime.
Regards,
Prashant
On Wed, Mar 23, 2011 at 9:22 PM, Michael Dick <mi...@gmail.com>wrote:
> I haven't had a chance to look at your example application, but I think we
> need to make some changes to the way we handle proxies.
>
> Currently there's no way to prevent proxies from being inserted. It's not
> intuitive when they will be inserted, and they can be tough to remove. What
> I'd propose is to make it work something like this :
>
> if openjpa.ProxyManager.TrackChanges == False :
> # No proxies are inserted. Ever.
>
> else :
>
> if openjpa.DetachState.DetachedStateField == "true":
> # proxies are inserted when the entity is flushed (or committed)
> # proxies are not removed when the entity is detached
> # proxies are not removed when the entity is serialized
>
> elif openjpa.DetachState.DetachedStateField == "transient" :
> # proxies are inserted when the entity is flushed (or committed)
> # proxies are not removed when the entity is detached
> # proxies are removed when the entity is serialized
>
> elif openjpa.DetachState.DetachedStateField == "false" :
> # proxies are inserted when the entity is flushed (or committed)
> # proxies are removed when the entity is detached
> # proxies are removed when the entity is serialized
>
> From what I've seen none of these are accurate for trunk, and the related
> code path is a bit tangled (or I just haven't groked it).
>
> For your specific use case, would you want the proxies to ever be inserted?
>
> -mike
>
>