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Posted to users@tapestry.apache.org by "Firas A." <ta...@idigna.com> on 2006/05/18 19:26:28 UTC
Persistence misbehavior in T4
Hello Everyone!
I have a class, CategoryBrowser of type BasePage which has a transient
property, a JavaBean called ProductCategory. ProductCategory makes use of an
instance field:
private List<Category> subCategories = null;
This list is initialized in CategoryBrowser upon every request. Every access
to subCategories is synchronized. In the CategoryBrowser.pageDetached() the
ProductCategory property is set to null.
The problem:
The state of the subCategories field is retained between requests. During
all subsequent requests after the 1st one, the initial value of
subCategories is not null (dispite the declaration above).
And when this happens the current state of subCategories may even be
observed in another browser/session. Here's the test that I performed:
1. initiate the misbehavior in Firefox
2. close Firefox and start Opera
3. browse to the page where subCategories is first initialized
The result: the state of subCategories reflects the state it got in Firefox
(1), i.e. it is was not null upon first request and already contained some
values from the session in Firefox.
Any idea on what's going on?
My platform:
Tapestry 4.0.1 (started with -Dorg.apache.tapestry.disable-caching=true)
JVM 1.5.0_06-b05 / WinXP SP2
Tomcat 5.5.9
Latest Firefox, Opera and MSIE
Thank you for your time!
</Firas>
RE: RESOLVED Persistence misbehavior in T4
Posted by "Firas A." <ta...@idigna.com>.
Hi Paul,
I found the source of my problem. Luckily and it has nothing to do with
Tapestry. Tapestry gets a list of ProductCategory beans from iBatis' cache.
Remember, ProductCategory which contains the troublesome subCategories
field?
My solution was to clone the ProductCategory objest, returned by iBatis,
before making it available to Tapestry.
Cheers,
</Firas>
-----Original Message-----
From: Paul Cantrell [mailto:cantrell@pobox.com]
Sent: den 19 maj 2006 16:57
To: Tapestry users
Subject: Re: Persistence misbehavior in T4
Is the Bean shared across pages? If it is a Tapestry @Bean, I really don't
think you need to synchronize on it, either. You may, however, need to clear
it out between requests.
Maybe others can clarify: does Tapestry pool bean instances?
P
On May 19, 2006, at 2:48 AM, Firas A. wrote:
>
> Paul: "You should generally not need to synchronize access to instance
> fields of a page."
> Firas: The synchronized methods are in the JavaBean class containing
> the subCategories field, not in a page class. Which answers your
> question.
>
> A little clarification:
> CategoryBrowser is a page class (typeof BasePage).
> CategoryBrowser uses an instance field, ProductCategory (a javabean)
> ProductCategory uses an instance field, subCategories of type List All
> operations on subCategories (in ProductCategory!) are synchronized
>
> It's the subCategories that's been kept in memory.
>
> Regards,
>
> </Firas>
>
> -----Original Message-----
> From: Paul Cantrell [mailto:cantrell@pobox.com]
> Sent: den 18 maj 2006 19:39
> To: Tapestry users
> Subject: Re: Persistence misbehavior in T4
>
> A few general points:
>
> -- An "= null" initializer for a non-final field is redundant in all
> cases.
> -- You should generally not need to synchronize access to instance
> fields of a page.
>
> Now a question:
>
>> In the CategoryBrowser.pageDetached() the ProductCategory property is
>> set to null.
>
> Don't you mean subCategories is set to null? If it's not, then that's
> your problem. Page objects get reused.
>
> Cheers,
>
> Paul
>
> On May 18, 2006, at 12:26 PM, Firas A. wrote:
>
>> Hello Everyone!
>>
>> I have a class, CategoryBrowser of type BasePage which has a
>> transient property, a JavaBean called ProductCategory.
>> ProductCategory makes use of an instance field:
>> private List<Category> subCategories = null;
>>
>> This list is initialized in CategoryBrowser upon every request.
>> Every access
>> to subCategories is synchronized. In the
>> CategoryBrowser.pageDetached() the
>> ProductCategory property is set to null.
>>
>> The problem:
>> The state of the subCategories field is retained between requests.
>> During
>> all subsequent requests after the 1st one, the initial value of
>> subCategories is not null (dispite the declaration above).
>>
>> And when this happens the current state of subCategories may even be
>> observed in another browser/session. Here's the test that I
>> performed:
>>
>> 1. initiate the misbehavior in Firefox
>>
>> 2. close Firefox and start Opera
>>
>> 3. browse to the page where subCategories is first initialized
>>
>> The result: the state of subCategories reflects the state it got in
>> Firefox (1), i.e. it is was not null upon first request and already
>> contained some values from the session in Firefox.
>>
>> Any idea on what's going on?
>>
>> My platform:
>> Tapestry 4.0.1 (started with -Dorg.apache.tapestry.disable-
>> caching=true)
>> JVM 1.5.0_06-b05 / WinXP SP2
>> Tomcat 5.5.9
>> Latest Firefox, Opera and MSIE
>>
>>
>> Thank you for your time!
>>
>> </Firas>
>>
>
> _________________________________________________________________
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> http://innig.net
>
>
>
>
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Re: Persistence misbehavior in T4
Posted by Paul Cantrell <ca...@pobox.com>.
Is the Bean shared across pages? If it is a Tapestry @Bean, I really
don't think you need to synchronize on it, either. You may, however,
need to clear it out between requests.
Maybe others can clarify: does Tapestry pool bean instances?
P
On May 19, 2006, at 2:48 AM, Firas A. wrote:
>
> Paul: "You should generally not need to synchronize access to instance
> fields of a page."
> Firas: The synchronized methods are in the JavaBean class
> containing the
> subCategories field, not in a page class. Which answers your question.
>
> A little clarification:
> CategoryBrowser is a page class (typeof BasePage).
> CategoryBrowser uses an instance field, ProductCategory (a javabean)
> ProductCategory uses an instance field, subCategories of type List
> All operations on subCategories (in ProductCategory!) are synchronized
>
> It's the subCategories that's been kept in memory.
>
> Regards,
>
> </Firas>
>
> -----Original Message-----
> From: Paul Cantrell [mailto:cantrell@pobox.com]
> Sent: den 18 maj 2006 19:39
> To: Tapestry users
> Subject: Re: Persistence misbehavior in T4
>
> A few general points:
>
> -- An "= null" initializer for a non-final field is redundant in
> all cases.
> -- You should generally not need to synchronize access to instance
> fields of
> a page.
>
> Now a question:
>
>> In the CategoryBrowser.pageDetached() the ProductCategory property is
>> set to null.
>
> Don't you mean subCategories is set to null? If it's not, then
> that's your
> problem. Page objects get reused.
>
> Cheers,
>
> Paul
>
> On May 18, 2006, at 12:26 PM, Firas A. wrote:
>
>> Hello Everyone!
>>
>> I have a class, CategoryBrowser of type BasePage which has a
>> transient
>> property, a JavaBean called ProductCategory. ProductCategory makes
>> use
>> of an instance field:
>> private List<Category> subCategories = null;
>>
>> This list is initialized in CategoryBrowser upon every request.
>> Every access
>> to subCategories is synchronized. In the
>> CategoryBrowser.pageDetached() the
>> ProductCategory property is set to null.
>>
>> The problem:
>> The state of the subCategories field is retained between requests.
>> During
>> all subsequent requests after the 1st one, the initial value of
>> subCategories is not null (dispite the declaration above).
>>
>> And when this happens the current state of subCategories may even be
>> observed in another browser/session. Here's the test that I
>> performed:
>>
>> 1. initiate the misbehavior in Firefox
>>
>> 2. close Firefox and start Opera
>>
>> 3. browse to the page where subCategories is first initialized
>>
>> The result: the state of subCategories reflects the state it got in
>> Firefox (1), i.e. it is was not null upon first request and already
>> contained some values from the session in Firefox.
>>
>> Any idea on what's going on?
>>
>> My platform:
>> Tapestry 4.0.1 (started with -Dorg.apache.tapestry.disable-
>> caching=true)
>> JVM 1.5.0_06-b05 / WinXP SP2
>> Tomcat 5.5.9
>> Latest Firefox, Opera and MSIE
>>
>>
>> Thank you for your time!
>>
>> </Firas>
>>
>
> _________________________________________________________________
> Piano music podcast: http://inthehands.com Other interesting stuff:
> http://innig.net
>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
>
_________________________________________________________________
Piano music podcast: http://inthehands.com
Other interesting stuff: http://innig.net
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
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RE: Persistence misbehavior in T4
Posted by "Firas A." <ta...@idigna.com>.
Paul: "You should generally not need to synchronize access to instance
fields of a page."
Firas: The synchronized methods are in the JavaBean class containing the
subCategories field, not in a page class. Which answers your question.
A little clarification:
CategoryBrowser is a page class (typeof BasePage).
CategoryBrowser uses an instance field, ProductCategory (a javabean)
ProductCategory uses an instance field, subCategories of type List
All operations on subCategories (in ProductCategory!) are synchronized
It's the subCategories that's been kept in memory.
Regards,
</Firas>
-----Original Message-----
From: Paul Cantrell [mailto:cantrell@pobox.com]
Sent: den 18 maj 2006 19:39
To: Tapestry users
Subject: Re: Persistence misbehavior in T4
A few general points:
-- An "= null" initializer for a non-final field is redundant in all cases.
-- You should generally not need to synchronize access to instance fields of
a page.
Now a question:
> In the CategoryBrowser.pageDetached() the ProductCategory property is
> set to null.
Don't you mean subCategories is set to null? If it's not, then that's your
problem. Page objects get reused.
Cheers,
Paul
On May 18, 2006, at 12:26 PM, Firas A. wrote:
> Hello Everyone!
>
> I have a class, CategoryBrowser of type BasePage which has a transient
> property, a JavaBean called ProductCategory. ProductCategory makes use
> of an instance field:
> private List<Category> subCategories = null;
>
> This list is initialized in CategoryBrowser upon every request.
> Every access
> to subCategories is synchronized. In the
> CategoryBrowser.pageDetached() the
> ProductCategory property is set to null.
>
> The problem:
> The state of the subCategories field is retained between requests.
> During
> all subsequent requests after the 1st one, the initial value of
> subCategories is not null (dispite the declaration above).
>
> And when this happens the current state of subCategories may even be
> observed in another browser/session. Here's the test that I performed:
>
> 1. initiate the misbehavior in Firefox
>
> 2. close Firefox and start Opera
>
> 3. browse to the page where subCategories is first initialized
>
> The result: the state of subCategories reflects the state it got in
> Firefox (1), i.e. it is was not null upon first request and already
> contained some values from the session in Firefox.
>
> Any idea on what's going on?
>
> My platform:
> Tapestry 4.0.1 (started with -Dorg.apache.tapestry.disable-
> caching=true)
> JVM 1.5.0_06-b05 / WinXP SP2
> Tomcat 5.5.9
> Latest Firefox, Opera and MSIE
>
>
> Thank you for your time!
>
> </Firas>
>
_________________________________________________________________
Piano music podcast: http://inthehands.com Other interesting stuff:
http://innig.net
---------------------------------------------------------------------
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Re: Persistence misbehavior in T4
Posted by Paul Cantrell <ca...@pobox.com>.
A few general points:
-- An "= null" initializer for a non-final field is redundant in all
cases.
-- You should generally not need to synchronize access to instance
fields of a page.
Now a question:
> In the CategoryBrowser.pageDetached() the ProductCategory property
> is set to null.
Don't you mean subCategories is set to null? If it's not, then that's
your problem. Page objects get reused.
Cheers,
Paul
On May 18, 2006, at 12:26 PM, Firas A. wrote:
> Hello Everyone!
>
> I have a class, CategoryBrowser of type BasePage which has a transient
> property, a JavaBean called ProductCategory. ProductCategory makes
> use of an
> instance field:
> private List<Category> subCategories = null;
>
> This list is initialized in CategoryBrowser upon every request.
> Every access
> to subCategories is synchronized. In the
> CategoryBrowser.pageDetached() the
> ProductCategory property is set to null.
>
> The problem:
> The state of the subCategories field is retained between requests.
> During
> all subsequent requests after the 1st one, the initial value of
> subCategories is not null (dispite the declaration above).
>
> And when this happens the current state of subCategories may even be
> observed in another browser/session. Here's the test that I performed:
>
> 1. initiate the misbehavior in Firefox
>
> 2. close Firefox and start Opera
>
> 3. browse to the page where subCategories is first initialized
>
> The result: the state of subCategories reflects the state it got in
> Firefox
> (1), i.e. it is was not null upon first request and already
> contained some
> values from the session in Firefox.
>
> Any idea on what's going on?
>
> My platform:
> Tapestry 4.0.1 (started with -Dorg.apache.tapestry.disable-
> caching=true)
> JVM 1.5.0_06-b05 / WinXP SP2
> Tomcat 5.5.9
> Latest Firefox, Opera and MSIE
>
>
> Thank you for your time!
>
> </Firas>
>
_________________________________________________________________
Piano music podcast: http://inthehands.com
Other interesting stuff: http://innig.net
---------------------------------------------------------------------
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RE: Persistence misbehavior in T4
Posted by "Firas A." <ta...@idigna.com>.
Martin: ...sounds like you simply forgot "CategoryBrowser implements
PageDetachListener"
No Martin, I didn't. It's through PageDetachListener interface that i become
acquainted with pageDetach().
Thanks for your time.
</Firas>
-----Original Message-----
Hmm... sounds like you simply forgot "CategoryBrowser implements
PageDetachListener". Tapestry would then not understand that you want it to
call pageDetached(...).
Martin
On Thursday 18 May 2006 19:26, Firas A. wrote:
> Hello Everyone!
>
> I have a class, CategoryBrowser of type BasePage which has a transient
> property, a JavaBean called ProductCategory. ProductCategory makes use
> of an instance field:
> private List<Category> subCategories = null;
>
> This list is initialized in CategoryBrowser upon every request. Every
> access to subCategories is synchronized. In the
> CategoryBrowser.pageDetached() the ProductCategory property is set to
null.
>
> The problem:
> The state of the subCategories field is retained between requests.
> During all subsequent requests after the 1st one, the initial value of
> subCategories is not null (dispite the declaration above).
>
> And when this happens the current state of subCategories may even be
> observed in another browser/session. Here's the test that I performed:
>
> 1. initiate the misbehavior in Firefox
>
> 2. close Firefox and start Opera
>
> 3. browse to the page where subCategories is first initialized
>
> The result: the state of subCategories reflects the state it got in
> Firefox (1), i.e. it is was not null upon first request and already
> contained some values from the session in Firefox.
>
> Any idea on what's going on?
>
> My platform:
> Tapestry 4.0.1 (started with
> -Dorg.apache.tapestry.disable-caching=true)
> JVM 1.5.0_06-b05 / WinXP SP2
> Tomcat 5.5.9
> Latest Firefox, Opera and MSIE
>
>
> Thank you for your time!
>
> </Firas>
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Re: Persistence misbehavior in T4
Posted by Martin <ma...@entcap.se>.
Hmm... sounds like you simply forgot "CategoryBrowser implements
PageDetachListener". Tapestry would then not understand that you want it to
call pageDetached(...).
Martin
On Thursday 18 May 2006 19:26, Firas A. wrote:
> Hello Everyone!
>
> I have a class, CategoryBrowser of type BasePage which has a transient
> property, a JavaBean called ProductCategory. ProductCategory makes use of
> an instance field:
> private List<Category> subCategories = null;
>
> This list is initialized in CategoryBrowser upon every request. Every
> access to subCategories is synchronized. In the
> CategoryBrowser.pageDetached() the ProductCategory property is set to null.
>
> The problem:
> The state of the subCategories field is retained between requests. During
> all subsequent requests after the 1st one, the initial value of
> subCategories is not null (dispite the declaration above).
>
> And when this happens the current state of subCategories may even be
> observed in another browser/session. Here's the test that I performed:
>
> 1. initiate the misbehavior in Firefox
>
> 2. close Firefox and start Opera
>
> 3. browse to the page where subCategories is first initialized
>
> The result: the state of subCategories reflects the state it got in Firefox
> (1), i.e. it is was not null upon first request and already contained some
> values from the session in Firefox.
>
> Any idea on what's going on?
>
> My platform:
> Tapestry 4.0.1 (started with -Dorg.apache.tapestry.disable-caching=true)
> JVM 1.5.0_06-b05 / WinXP SP2
> Tomcat 5.5.9
> Latest Firefox, Opera and MSIE
>
>
> Thank you for your time!
>
> </Firas>
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