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Posted to users@wicket.apache.org by Christian Helmbold <ch...@yahoo.de> on 2009/05/06 20:29:45 UTC
Lazy Open Session In View with AOP
Hello,
I want to use the Open Session In View Pattern with Wicket, but I don't want to open a Hibernate Session for every request like the ServletFilter approach does.
I looked at the "lazy-loading Open Session in View" for JPA implementation from Wille Faler. http://faler.wordpress.com/2009/04/30/building-a-more-scalable-open-session-in-view/ He uses AOP instead of a ServletFilter to intercept only those method calls that need an EntityManager.
My plan is to build something similar for Hibernate with Spring AOP. The solutions would consist of the following steps:
1. An aspect creates a new Hibernate Session, if a method is called, that needs one and none is already open.
2. The transaction runs.
3. The RequestCycle commits the transaction and closes the session. Or rollback, if an exception was thrown.
Is something wrong with it?
The Hibernate Reference says: "When the transaction ends, either through commit or roll back, the "current" Session is closed automatically."
https://www.hibernate.org/42.html#A6
This means that only one transaction can be executed in one request, right? But what is, if I need more than one transaction per request? Since I have to hold the session open during rendering, because of lazy loading, I cannot commit a transaction if I don't know another Session will be opened immediately and not to be closed until the end of the request cycle.
Hibernate typically bounds the Session to the current thread. But was is the current thread in a Wicket Application? Are those threads pooled? Could the same session be used in two requests, when no commit happened?
Thanks in advance,
Christian
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Re: Lazy Open Session In View with AOP
Posted by James Carman <jc...@carmanconsulting.com>.
On Thu, May 7, 2009 at 8:53 AM, Christian Helmbold
<ch...@yahoo.de> wrote:
>
> Thanks for your answer, James.
>
> I try to understand magic things. The missing peace in the puzzle was the difference between Hibernates openSession() and getCurrentSession(). More than one transaction within one session seems only to be possible with openSession() and manual flushing and closing.
> http://www.techfaq360.com/hibernate_interview_questions.jsp?qid=241
>
> This is a pure Hibernate concern, but I want to post an important of the answer to my initial question.
>
> The question "What is the current thread, the Hibernate Session is bound to, in a Wicket application?" is still open.
The current thread is the request thread.
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AW: Lazy Open Session In View with AOP
Posted by Christian Helmbold <ch...@yahoo.de>.
Thanks for your answer, James.
I try to understand magic things. The missing peace in the puzzle was the difference between Hibernates openSession() and getCurrentSession(). More than one transaction within one session seems only to be possible with openSession() and manual flushing and closing.
http://www.techfaq360.com/hibernate_interview_questions.jsp?qid=241
This is a pure Hibernate concern, but I want to post an important of the answer to my initial question.
The question "What is the current thread, the Hibernate Session is bound to, in a Wicket application?" is still open.
----- Ursprüngliche Mail ----
> Von: James Carman <jc...@carmanconsulting.com>
> An: users@wicket.apache.org
> Gesendet: Mittwoch, den 6. Mai 2009, 22:13:09 Uhr
> Betreff: Re: Lazy Open Session In View with AOP
>
> If you use the @Transactional annotation (or define your transactions
> in the XML), Spring will take care of the transactions for you
> automagically.
Thanks,
Christian
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Re: Lazy Open Session In View with AOP
Posted by James Carman <jc...@carmanconsulting.com>.
If you use the @Transactional annotation (or define your transactions
in the XML), Spring will take care of the transactions for you
automagically.
On Wed, May 6, 2009 at 3:05 PM, Christian Helmbold
<ch...@yahoo.de> wrote:
>
> Thanks for this hint.
>
> The Spring API doc says:
>
> "If set to "false", each data access operation or transaction will use its own session (like without Open Session in View). Each of those sessions will be registered for deferred close, though, actually processed at request completion."
> http://static.springframework.org/spring/docs/2.5.x/api/org/springframework/orm/hibernate3/support/OpenSessionInViewFilter.html#setSingleSession(boolean)
>
> I don't understand who sessions are opened with this setting.
>
>
>
>
> ----- Ursprüngliche Mail ----
>> Von: James Carman <jc...@carmanconsulting.com>
>> An: users@wicket.apache.org
>> Gesendet: Mittwoch, den 6. Mai 2009, 20:34:27 Uhr
>> Betreff: Re: Lazy Open Session In View with AOP
>>
>> You can try using the filter, just set the singleSession property to false.
>
>
>
>
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AW: Lazy Open Session In View with AOP
Posted by Christian Helmbold <ch...@yahoo.de>.
Thanks for this hint.
The Spring API doc says:
"If set to "false", each data access operation or transaction will use its own session (like without Open Session in View). Each of those sessions will be registered for deferred close, though, actually processed at request completion."
http://static.springframework.org/spring/docs/2.5.x/api/org/springframework/orm/hibernate3/support/OpenSessionInViewFilter.html#setSingleSession(boolean)
I don't understand who sessions are opened with this setting.
----- Ursprüngliche Mail ----
> Von: James Carman <jc...@carmanconsulting.com>
> An: users@wicket.apache.org
> Gesendet: Mittwoch, den 6. Mai 2009, 20:34:27 Uhr
> Betreff: Re: Lazy Open Session In View with AOP
>
> You can try using the filter, just set the singleSession property to false.
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Re: Lazy Open Session In View with AOP
Posted by James Carman <jc...@carmanconsulting.com>.
You can try using the filter, just set the singleSession property to false.
On Wed, May 6, 2009 at 2:29 PM, Christian Helmbold
<ch...@yahoo.de> wrote:
>
> Hello,
>
> I want to use the Open Session In View Pattern with Wicket, but I don't want to open a Hibernate Session for every request like the ServletFilter approach does.
>
> I looked at the "lazy-loading Open Session in View" for JPA implementation from Wille Faler. http://faler.wordpress.com/2009/04/30/building-a-more-scalable-open-session-in-view/ He uses AOP instead of a ServletFilter to intercept only those method calls that need an EntityManager.
>
> My plan is to build something similar for Hibernate with Spring AOP. The solutions would consist of the following steps:
>
> 1. An aspect creates a new Hibernate Session, if a method is called, that needs one and none is already open.
> 2. The transaction runs.
> 3. The RequestCycle commits the transaction and closes the session. Or rollback, if an exception was thrown.
>
> Is something wrong with it?
>
> The Hibernate Reference says: "When the transaction ends, either through commit or roll back, the "current" Session is closed automatically."
> https://www.hibernate.org/42.html#A6
>
> This means that only one transaction can be executed in one request, right? But what is, if I need more than one transaction per request? Since I have to hold the session open during rendering, because of lazy loading, I cannot commit a transaction if I don't know another Session will be opened immediately and not to be closed until the end of the request cycle.
>
> Hibernate typically bounds the Session to the current thread. But was is the current thread in a Wicket Application? Are those threads pooled? Could the same session be used in two requests, when no commit happened?
>
> Thanks in advance,
> Christian
>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
> For additional commands, e-mail: users-help@wicket.apache.org
>
>
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AW: Lazy Open Session In View with AOP
Posted by Christian Helmbold <ch...@yahoo.de>.
Thanks for your answer.
I know the OpenSessionInViewFilterfrom Spring, but it opens a new Hibernate Session for every request even if you request an image.
----- Ursprüngliche Mail ----
> Von: Carlo Camerino <cm...@gmail.com>
> An: users@wicket.apache.org
> Gesendet: Mittwoch, den 6. Mai 2009, 20:33:44 Uhr
> Betreff: Re: Lazy Open Session In View with AOP
>
> spring has implemented itw own opensessioninview filter.,
> i dont' think that you have to crete your own
>
> Spring has a class like this which you can declare in your web.xml
> OpenSessionInViewFilter
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Re: Lazy Open Session In View with AOP
Posted by Carlo Camerino <cm...@gmail.com>.
spring has implemented itw own opensessioninview filter.,
i dont' think that you have to crete your own
Spring has a class like this which you can declare in your web.xml
OpenSessionInViewFilter
On Thu, May 7, 2009 at 2:29 AM, Christian Helmbold
<ch...@yahoo.de> wrote:
>
> Hello,
>
> I want to use the Open Session In View Pattern with Wicket, but I don't want to open a Hibernate Session for every request like the ServletFilter approach does.
>
> I looked at the "lazy-loading Open Session in View" for JPA implementation from Wille Faler. http://faler.wordpress.com/2009/04/30/building-a-more-scalable-open-session-in-view/ He uses AOP instead of a ServletFilter to intercept only those method calls that need an EntityManager.
>
> My plan is to build something similar for Hibernate with Spring AOP. The solutions would consist of the following steps:
>
> 1. An aspect creates a new Hibernate Session, if a method is called, that needs one and none is already open.
> 2. The transaction runs.
> 3. The RequestCycle commits the transaction and closes the session. Or rollback, if an exception was thrown.
>
> Is something wrong with it?
>
> The Hibernate Reference says: "When the transaction ends, either through commit or roll back, the "current" Session is closed automatically."
> https://www.hibernate.org/42.html#A6
>
> This means that only one transaction can be executed in one request, right? But what is, if I need more than one transaction per request? Since I have to hold the session open during rendering, because of lazy loading, I cannot commit a transaction if I don't know another Session will be opened immediately and not to be closed until the end of the request cycle.
>
> Hibernate typically bounds the Session to the current thread. But was is the current thread in a Wicket Application? Are those threads pooled? Could the same session be used in two requests, when no commit happened?
>
> Thanks in advance,
> Christian
>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
> For additional commands, e-mail: users-help@wicket.apache.org
>
>
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