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Posted to user@struts.apache.org by Burton Rhodes <bu...@gmail.com> on 2009/03/18 18:30:28 UTC
[S2] Struts 2 + Spring 2 + JPA example uses @PersistenceContext - is
this a "bad thing"??
I set up the example for "Struts 2 + Spring 2 + JPA + AJAX" using the
OpenEntityManagerInViewFilter from the Struts website and all works
well. (http://struts.apache.org/2.0.14/docs/struts-2-spring-2-jpa-ajax.html).
It appears this example uses the @PersistenceContext annotation to
inject the EntityManger into each Service/Dao class...
Then I read this blog about how you SHOULD NOT use @PersistenceContext
annotation in a webapp becasue of thread safety unless you implement a
SingleThreadModel.
http://weblogs.java.net/blog/ss141213/archive/2005/12/dont_use_persis_1.html
Now I am confused... Should I instead use @PersistenceUnit to inject
the EntityManagerFactor into each Dao object? And if so, won't this
affect the OpenEntityManagerInViewFilter and cause Lazy exceptions?
Can someone shead some light on this for me or am I not understanding
this correctly?
Apologies in advance if this is a bit off Struts topic...
Thanks,
Burton
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Re: [S2] Struts 2 + Spring 2 + JPA example uses @PersistenceContext -
is this a "bad thing"??
Posted by Burton Rhodes <bu...@gmail.com>.
Many thanks for your efforts. I do have everyting in appcontext file.
I am using @Transactional and I am not using jpasupport. Let me know
what you find out and if jpasupport is necessary.
On 3/18/09, Wes Wannemacher <we...@wantii.com> wrote:
> I haven't read that blog post, but I do know that Spring treats
> @PersistenceContext differently than an EJB container. If you've
> configured everything within applicationContext.xml, rather than in
> the AppServer, and if you are extending JpaDaoSupport then I would
> think it should work properly. I will check it out tonight if I get a
> chance.
>
> -Wes
>
> On Wed, Mar 18, 2009 at 1:39 PM, Musachy Barroso <mu...@gmail.com> wrote:
>> I had no idea it was not thread safe, in that case it is probably a
>> good idea to get factory and create an entity manager every time.
>>
>> musachy
>>
>> On Wed, Mar 18, 2009 at 1:30 PM, Burton Rhodes <bu...@gmail.com>
>> wrote:
>>> I set up the example for "Struts 2 + Spring 2 + JPA + AJAX" using the
>>> OpenEntityManagerInViewFilter from the Struts website and all works
>>> well.
>>> (http://struts.apache.org/2.0.14/docs/struts-2-spring-2-jpa-ajax.html).
>>> It appears this example uses the @PersistenceContext annotation to
>>> inject the EntityManger into each Service/Dao class...
>>>
>>> Then I read this blog about how you SHOULD NOT use @PersistenceContext
>>> annotation in a webapp becasue of thread safety unless you implement a
>>> SingleThreadModel.
>>>
>>> http://weblogs.java.net/blog/ss141213/archive/2005/12/dont_use_persis_1.html
>>>
>>> Now I am confused... Should I instead use @PersistenceUnit to inject
>>> the EntityManagerFactor into each Dao object? And if so, won't this
>>> affect the OpenEntityManagerInViewFilter and cause Lazy exceptions?
>>> Can someone shead some light on this for me or am I not understanding
>>> this correctly?
>>>
>>> Apologies in advance if this is a bit off Struts topic...
>>>
>>> Thanks,
>>> Burton
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>>> For additional commands, e-mail: user-help@struts.apache.org
>>>
>>>
>>
>>
>>
>> --
>> "Hey you! Would you help me to carry the stone?" Pink Floyd
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>> For additional commands, e-mail: user-help@struts.apache.org
>>
>>
>
>
>
> --
> Wes Wannemacher
> Author - Struts 2 In Practice
> Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
> http://www.manning.com/wannemacher
>
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> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
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>
>
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Re: [S2] Struts 2 + Spring 2 + JPA example uses @PersistenceContext -
is this a "bad thing"??
Posted by Wes Wannemacher <we...@wantii.com>.
I haven't read that blog post, but I do know that Spring treats
@PersistenceContext differently than an EJB container. If you've
configured everything within applicationContext.xml, rather than in
the AppServer, and if you are extending JpaDaoSupport then I would
think it should work properly. I will check it out tonight if I get a
chance.
-Wes
On Wed, Mar 18, 2009 at 1:39 PM, Musachy Barroso <mu...@gmail.com> wrote:
> I had no idea it was not thread safe, in that case it is probably a
> good idea to get factory and create an entity manager every time.
>
> musachy
>
> On Wed, Mar 18, 2009 at 1:30 PM, Burton Rhodes <bu...@gmail.com> wrote:
>> I set up the example for "Struts 2 + Spring 2 + JPA + AJAX" using the
>> OpenEntityManagerInViewFilter from the Struts website and all works
>> well. (http://struts.apache.org/2.0.14/docs/struts-2-spring-2-jpa-ajax.html).
>> It appears this example uses the @PersistenceContext annotation to
>> inject the EntityManger into each Service/Dao class...
>>
>> Then I read this blog about how you SHOULD NOT use @PersistenceContext
>> annotation in a webapp becasue of thread safety unless you implement a
>> SingleThreadModel.
>>
>> http://weblogs.java.net/blog/ss141213/archive/2005/12/dont_use_persis_1.html
>>
>> Now I am confused... Should I instead use @PersistenceUnit to inject
>> the EntityManagerFactor into each Dao object? And if so, won't this
>> affect the OpenEntityManagerInViewFilter and cause Lazy exceptions?
>> Can someone shead some light on this for me or am I not understanding
>> this correctly?
>>
>> Apologies in advance if this is a bit off Struts topic...
>>
>> Thanks,
>> Burton
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>> For additional commands, e-mail: user-help@struts.apache.org
>>
>>
>
>
>
> --
> "Hey you! Would you help me to carry the stone?" Pink Floyd
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> For additional commands, e-mail: user-help@struts.apache.org
>
>
--
Wes Wannemacher
Author - Struts 2 In Practice
Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
http://www.manning.com/wannemacher
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Re: [S2] Struts 2 + Spring 2 + JPA example uses @PersistenceContext -
is this a "bad thing"??
Posted by Musachy Barroso <mu...@gmail.com>.
I have no idea :)
musachy
On Wed, Mar 18, 2009 at 1:52 PM, Burton Rhodes <bu...@gmail.com> wrote:
> Any thoughts on how this would affect the
> OpenEntityManagerInViewFilter? I assume if you create a new EM for
> each service/dao operation, the objects would become detached after
> each method thus giving you a lazy exception for anything in the view
> - rendering the OpenEntityManagerInViewFilter useless. Am I
> understanding this correctly?
>
> On Wed, Mar 18, 2009 at 12:39 PM, Musachy Barroso <mu...@gmail.com> wrote:
>> I had no idea it was not thread safe, in that case it is probably a
>> good idea to get factory and create an entity manager every time.
>>
>> musachy
>>
>> On Wed, Mar 18, 2009 at 1:30 PM, Burton Rhodes <bu...@gmail.com> wrote:
>>> I set up the example for "Struts 2 + Spring 2 + JPA + AJAX" using the
>>> OpenEntityManagerInViewFilter from the Struts website and all works
>>> well. (http://struts.apache.org/2.0.14/docs/struts-2-spring-2-jpa-ajax.html).
>>> It appears this example uses the @PersistenceContext annotation to
>>> inject the EntityManger into each Service/Dao class...
>>>
>>> Then I read this blog about how you SHOULD NOT use @PersistenceContext
>>> annotation in a webapp becasue of thread safety unless you implement a
>>> SingleThreadModel.
>>>
>>> http://weblogs.java.net/blog/ss141213/archive/2005/12/dont_use_persis_1.html
>>>
>>> Now I am confused... Should I instead use @PersistenceUnit to inject
>>> the EntityManagerFactor into each Dao object? And if so, won't this
>>> affect the OpenEntityManagerInViewFilter and cause Lazy exceptions?
>>> Can someone shead some light on this for me or am I not understanding
>>> this correctly?
>>>
>>> Apologies in advance if this is a bit off Struts topic...
>>>
>>> Thanks,
>>> Burton
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>>> For additional commands, e-mail: user-help@struts.apache.org
>>>
>>>
>>
>>
>>
>> --
>> "Hey you! Would you help me to carry the stone?" Pink Floyd
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>> For additional commands, e-mail: user-help@struts.apache.org
>>
>>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> For additional commands, e-mail: user-help@struts.apache.org
>
>
--
"Hey you! Would you help me to carry the stone?" Pink Floyd
---------------------------------------------------------------------
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Re: [S2] Struts 2 + Spring 2 + JPA example uses @PersistenceContext -
is this a "bad thing"??
Posted by Burton Rhodes <bu...@gmail.com>.
Any thoughts on how this would affect the
OpenEntityManagerInViewFilter? I assume if you create a new EM for
each service/dao operation, the objects would become detached after
each method thus giving you a lazy exception for anything in the view
- rendering the OpenEntityManagerInViewFilter useless. Am I
understanding this correctly?
On Wed, Mar 18, 2009 at 12:39 PM, Musachy Barroso <mu...@gmail.com> wrote:
> I had no idea it was not thread safe, in that case it is probably a
> good idea to get factory and create an entity manager every time.
>
> musachy
>
> On Wed, Mar 18, 2009 at 1:30 PM, Burton Rhodes <bu...@gmail.com> wrote:
>> I set up the example for "Struts 2 + Spring 2 + JPA + AJAX" using the
>> OpenEntityManagerInViewFilter from the Struts website and all works
>> well. (http://struts.apache.org/2.0.14/docs/struts-2-spring-2-jpa-ajax.html).
>> It appears this example uses the @PersistenceContext annotation to
>> inject the EntityManger into each Service/Dao class...
>>
>> Then I read this blog about how you SHOULD NOT use @PersistenceContext
>> annotation in a webapp becasue of thread safety unless you implement a
>> SingleThreadModel.
>>
>> http://weblogs.java.net/blog/ss141213/archive/2005/12/dont_use_persis_1.html
>>
>> Now I am confused... Should I instead use @PersistenceUnit to inject
>> the EntityManagerFactor into each Dao object? And if so, won't this
>> affect the OpenEntityManagerInViewFilter and cause Lazy exceptions?
>> Can someone shead some light on this for me or am I not understanding
>> this correctly?
>>
>> Apologies in advance if this is a bit off Struts topic...
>>
>> Thanks,
>> Burton
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>> For additional commands, e-mail: user-help@struts.apache.org
>>
>>
>
>
>
> --
> "Hey you! Would you help me to carry the stone?" Pink Floyd
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> For additional commands, e-mail: user-help@struts.apache.org
>
>
---------------------------------------------------------------------
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For additional commands, e-mail: user-help@struts.apache.org
Re: [S2] Struts 2 + Spring 2 + JPA example uses @PersistenceContext -
is this a "bad thing"??
Posted by Musachy Barroso <mu...@gmail.com>.
I had no idea it was not thread safe, in that case it is probably a
good idea to get factory and create an entity manager every time.
musachy
On Wed, Mar 18, 2009 at 1:30 PM, Burton Rhodes <bu...@gmail.com> wrote:
> I set up the example for "Struts 2 + Spring 2 + JPA + AJAX" using the
> OpenEntityManagerInViewFilter from the Struts website and all works
> well. (http://struts.apache.org/2.0.14/docs/struts-2-spring-2-jpa-ajax.html).
> It appears this example uses the @PersistenceContext annotation to
> inject the EntityManger into each Service/Dao class...
>
> Then I read this blog about how you SHOULD NOT use @PersistenceContext
> annotation in a webapp becasue of thread safety unless you implement a
> SingleThreadModel.
>
> http://weblogs.java.net/blog/ss141213/archive/2005/12/dont_use_persis_1.html
>
> Now I am confused... Should I instead use @PersistenceUnit to inject
> the EntityManagerFactor into each Dao object? And if so, won't this
> affect the OpenEntityManagerInViewFilter and cause Lazy exceptions?
> Can someone shead some light on this for me or am I not understanding
> this correctly?
>
> Apologies in advance if this is a bit off Struts topic...
>
> Thanks,
> Burton
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> For additional commands, e-mail: user-help@struts.apache.org
>
>
--
"Hey you! Would you help me to carry the stone?" Pink Floyd
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