Re: How to lock the access of methods within an action?

2006-05-30 Thread The Jasper 

Hi,

this sounds like a common database problem. You might want to consider
some kind of pessimistic locking. Basically you lock the object when
you start editing and prevent all access to it for the duration of the
lock. You could also do an optimistic lock which means that when you
change an object it will only be committed if the object hasn't
changed between the time you got your lock and the time you want to
commit it. This doens't prevent you from having done unnecessary work
however. Most db's support optimistic locking, but not pessimistic
locking.

If you want to use this at the application level you will have to do
it yourself. You could put a variable somewhere to track wether an
object is being edited and base access restrictions off of that.
However you have to be very carefull about making sure you don't get
any deadlock or race conditions.

I suggest you delve into database world and read about how other
people have solved this problem.

mvg,
Jasper

On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:

Hello everyone,



Within our struts web application in which we have edit-actions within a user 
can be busy editing data in the form for several minutes.

The problem is, if another user is also editing the data at the same time, one of the is 
eventually going to overwrite the changes of the other and the other will have worked 
completely in vain. So my question would be whether there's some way to prevent this from 
happening, some kind of lock down method for edit-actions? I think this 
problem is not uncommon, can someone give me a tip?



thanks in advance
Julian

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Re: Re: How to lock the access of methods within an action?

2006-05-30 Thread Julian Tillmann 
Thanks a lot for your answer!

My thinking behind is the application level!

I’m not sure but the goal is (my hope..)to solve

this problem using aspect oriented programming or Spring

although I’m not very aware of it.

For example it would be nice to have one central configuration there you 

can say:

this method -max-users 1- 

rule: throw error ….

Should be done then a second users wants access to the method.

Can you help me?

Thanks a lot!


  Original-Nachricht 
 Datum: Tue, 30 May 2006 10:55:17 +0200
 Von: The Jasper [EMAIL PROTECTED]
 An: Struts Users Mailing List user@struts.apache.org
 Betreff: Re: How to lock the access of methods within an action?
 #xA Hi,
 
 this sounds like a common database problem. You might want to consider
 some kind of pessimistic locking. Basically you lock the object when
 you start editing and prevent all access to it for the duration of the
 lock. You could also do an optimistic lock which means that when you
 change an object it will only be committed if the object hasn't
 changed between the time you got your lock and the time you want to
 commit it. This doens't prevent you from having done unnecessary work
 however. Most db's support optimistic locking, but not pessimistic
 locking.
 
 If you want to use this at the application level you will have to do
 it yourself. You could put a variable somewhere to track wether an
 object is being edited and base access restrictions off of that.
 However you have to be very carefull about making sure you don't get
 any deadlock or race conditions.
 
 I suggest you delve into database world and read about how other
 people have solved this problem.
 
 mvg,
 Jasper
 
 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
  Hello everyone,
 
  Within our struts web application in which we have edit-actions within
 a user can be busy editing data in the form for several minutes.
 
  The problem is, if another user is also editing the data at the same
 time, one of the is eventually going to overwrite the changes of the other and
 the other will have worked completely in vain. So my question would be
 whether there's some way to prevent this from happening, some kind of lock
 down method for edit-actions? I think this problem is not uncommon, can
 someone give me a tip?
 
  thanks in advance
  Julian
 
  --
 
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Re: Re: How to lock the access of methods within an action?

2006-05-30 Thread Lixin Chu 

i think transaction manager will take care of this.


On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:


Thanks a lot for your answer!

My thinking behind is the application level!

I'm not sure but the goal is (my hope..)to solve

this problem using aspect oriented programming or Spring

although I'm not very aware of it.

For example it would be nice to have one central configuration there you

can say:

this method -max-users 1-

rule: throw error ….

Should be done then a second users wants access to the method.

Can you help me?

Thanks a lot!


 Original-Nachricht 
Datum: Tue, 30 May 2006 10:55:17 +0200
Von: The Jasper [EMAIL PROTECTED]
An: Struts Users Mailing List user@struts.apache.org
Betreff: Re: How to lock the access of methods within an action?
#xA Hi,

 this sounds like a common database problem. You might want to consider
 some kind of pessimistic locking. Basically you lock the object when
 you start editing and prevent all access to it for the duration of the
 lock. You could also do an optimistic lock which means that when you
 change an object it will only be committed if the object hasn't
 changed between the time you got your lock and the time you want to
 commit it. This doens't prevent you from having done unnecessary work
 however. Most db's support optimistic locking, but not pessimistic
 locking.

 If you want to use this at the application level you will have to do
 it yourself. You could put a variable somewhere to track wether an
 object is being edited and base access restrictions off of that.
 However you have to be very carefull about making sure you don't get
 any deadlock or race conditions.

 I suggest you delve into database world and read about how other
 people have solved this problem.

 mvg,
 Jasper

 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
  Hello everyone,
 
  Within our struts web application in which we have edit-actions
within
 a user can be busy editing data in the form for several minutes.
 
  The problem is, if another user is also editing the data at the same
 time, one of the is eventually going to overwrite the changes of the
other and
 the other will have worked completely in vain. So my question would be
 whether there's some way to prevent this from happening, some kind of
lock
 down method for edit-actions? I think this problem is not uncommon, can
 someone give me a tip?
 
  thanks in advance
  Julian
 
  --
 
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Re: Re: Re: How to lock the access of methods within an action?

2006-05-30 Thread Julian Tillmann 
thx

hmm, where can I find it, is it part of Spring? 

  Original-Nachricht 
 Datum: Tue, 30 May 2006 18:36:06 +0800
 Von: Lixin Chu [EMAIL PROTECTED]
 An: Struts Users Mailing List user@struts.apache.org
 Betreff: Re: Re: How to lock the access of methods within an action?
 #xA i think transaction manager will take care of this.
 
 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
 
  Thanks a lot for your answer!
 
  My thinking behind is the application level!
 
  I'm not sure but the goal is (my hope..)to solve
 
  this problem using aspect oriented programming or Spring
 
  although I'm not very aware of it.
 
  For example it would be nice to have one central configuration there you
 
  can say:
 
  this method -max-users 1-
 
  rule: throw error ….
 
  Should be done then a second users wants access to the method.
 
  Can you help me?
 
  Thanks a lot!
 
   Original-Nachricht 
  Datum: Tue, 30 May 2006 10:55:17 +0200
  Von: The Jasper [EMAIL PROTECTED]
  An: Struts Users Mailing List user@struts.apache.org
  Betreff: Re: How to lock the access of methods within an action?
  #xA Hi,
  
   this sounds like a common database problem. You might want to consider
   some kind of pessimistic locking. Basically you lock the object when
   you start editing and prevent all access to it for the duration of the
   lock. You could also do an optimistic lock which means that when you
   change an object it will only be committed if the object hasn't
   changed between the time you got your lock and the time you want to
   commit it. This doens't prevent you from having done unnecessary work
   however. Most db's support optimistic locking, but not pessimistic
   locking.
  
   If you want to use this at the application level you will have to do
   it yourself. You could put a variable somewhere to track wether an
   object is being edited and base access restrictions off of that.
   However you have to be very carefull about making sure you don't get
   any deadlock or race conditions.
  
   I suggest you delve into database world and read about how other
   people have solved this problem.
  
   mvg,
   Jasper
  
   On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
Hello everyone,
   
Within our struts web application in which we have edit-actions
  within
   a user can be busy editing data in the form for several minutes.
   
The problem is, if another user is also editing the data at the same
   time, one of the is eventually going to overwrite the changes of the
  other and
   the other will have worked completely in vain. So my question would be
   whether there's some way to prevent this from happening, some kind of
  lock
   down method for edit-actions? I think this problem is not uncommon,
 can
   someone give me a tip?
   
thanks in advance
Julian
   
--
   
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 -
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Re: Re: Re: How to lock the access of methods within an action?

2006-05-30 Thread Miguel Galves 

Julian,

you can use the lock provided by Java 1.5 API...they are very simple to use.
For istance, I use java.util.concurrent.Semaphore.
The code above sho how to use it:
private Semaphore sceneryLock = new Semaphore(1, true);

 public void removeScenery() throws Exception {

   try {
   sceneryLock.acquire();

    do your critical stuff here ...
   } catch (InterruptedException e) {

   } finally {
   sceneryLock.release();
   }
   }


Hope it helps ...

[]s

Miguel

On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:


thx

hmm, where can I find it, is it part of Spring?

 Original-Nachricht 
Datum: Tue, 30 May 2006 18:36:06 +0800
Von: Lixin Chu [EMAIL PROTECTED]
An: Struts Users Mailing List user@struts.apache.org
Betreff: Re: Re: How to lock the access of methods within an action?
#xA i think transaction manager will take care of this.

 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
 
  Thanks a lot for your answer!
 
  My thinking behind is the application level!
 
  I'm not sure but the goal is (my hope..)to solve
 
  this problem using aspect oriented programming or Spring
 
  although I'm not very aware of it.
 
  For example it would be nice to have one central configuration there
you
 
  can say:
 
  this method -max-users 1-
 
  rule: throw error ….
 
  Should be done then a second users wants access to the method.
 
  Can you help me?
 
  Thanks a lot!
 
   Original-Nachricht 
  Datum: Tue, 30 May 2006 10:55:17 +0200
  Von: The Jasper [EMAIL PROTECTED]
  An: Struts Users Mailing List user@struts.apache.org
  Betreff: Re: How to lock the access of methods within an action?
  #xA Hi,
  
   this sounds like a common database problem. You might want to
consider
   some kind of pessimistic locking. Basically you lock the object when
   you start editing and prevent all access to it for the duration of
the
   lock. You could also do an optimistic lock which means that when you
   change an object it will only be committed if the object hasn't
   changed between the time you got your lock and the time you want to
   commit it. This doens't prevent you from having done unnecessary
work
   however. Most db's support optimistic locking, but not pessimistic
   locking.
  
   If you want to use this at the application level you will have to do
   it yourself. You could put a variable somewhere to track wether an
   object is being edited and base access restrictions off of that.
   However you have to be very carefull about making sure you don't get
   any deadlock or race conditions.
  
   I suggest you delve into database world and read about how other
   people have solved this problem.
  
   mvg,
   Jasper
  
   On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
Hello everyone,
   
Within our struts web application in which we have edit-actions
  within
   a user can be busy editing data in the form for several minutes.
   
The problem is, if another user is also editing the data at the
same
   time, one of the is eventually going to overwrite the changes of the
  other and
   the other will have worked completely in vain. So my question would
be
   whether there's some way to prevent this from happening, some kind
of
  lock
   down method for edit-actions? I think this problem is not uncommon,
 can
   someone give me a tip?
   
thanks in advance
Julian
   
--
   
Bis zu 70% Ihrer Onlinekosten sparen: GMX SmartSurfer!
  Kostenlos downloaden: http://www.gmx.net/de/go/smartsurfer
   
   
 -
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
   
  
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--
Miguel Galves - Engenheiro de Computação
Já leu meus blogs hoje?
Para geeks http://log4dev.blogspot.com
Pra pessoas normais
http://miguelgalves.blogspot.com

Não sabendo que era impossível, ele foi lá e fez...

Re: Re: Re: Re: How to lock the access of methods within an action?

2006-05-30 Thread Julian Tillmann 

Hi Miguel, 

thanks for the tip, is it possible to use this in a struts action which is not 
thread save?

ciao 4 now
Julian 

  Original-Nachricht 
 Datum: Tue, 30 May 2006 09:28:36 -0300
 Von: Miguel Galves [EMAIL PROTECTED]
 An: Struts Users Mailing List user@struts.apache.org
 Betreff: Re: Re: Re: How to lock the access of methods within an action?
 #xA Julian,
 
 you can use the lock provided by Java 1.5 API...they are very simple to
 use.
 For istance, I use java.util.concurrent.Semaphore.
 The code above sho how to use it:
 private Semaphore sceneryLock = new Semaphore(1, true);
 
   public void removeScenery() throws Exception {
 
 try {
 sceneryLock.acquire();
 
  do your critical stuff here ...
 } catch (InterruptedException e) {
 
 } finally {
 sceneryLock.release();
 }
 }
 
 Hope it helps ...
 
 []s
 
 Miguel
 
 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
 
  thx
 
  hmm, where can I find it, is it part of Spring?
 
   Original-Nachricht 
  Datum: Tue, 30 May 2006 18:36:06 +0800
  Von: Lixin Chu [EMAIL PROTECTED]
  An: Struts Users Mailing List user@struts.apache.org
  Betreff: Re: Re: How to lock the access of methods within an action?
  #xA i think transaction manager will take care of this.
  
   On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
   
Thanks a lot for your answer!
   
My thinking behind is the application level!
   
I'm not sure but the goal is (my hope..)to solve
   
this problem using aspect oriented programming or Spring
   
although I'm not very aware of it.
   
For example it would be nice to have one central configuration there
  you
   
can say:
   
this method -max-users 1-
   
rule: throw error ….
   
Should be done then a second users wants access to the method.
   
Can you help me?
   
Thanks a lot!
   
 Original-Nachricht 
Datum: Tue, 30 May 2006 10:55:17 +0200
Von: The Jasper [EMAIL PROTECTED]
An: Struts Users Mailing List user@struts.apache.org
Betreff: Re: How to lock the access of methods within an action?
#xA Hi,

 this sounds like a common database problem. You might want to
  consider
 some kind of pessimistic locking. Basically you lock the object
 when
 you start editing and prevent all access to it for the duration of
  the
 lock. You could also do an optimistic lock which means that when
 you
 change an object it will only be committed if the object hasn't
 changed between the time you got your lock and the time you want
 to
 commit it. This doens't prevent you from having done unnecessary
  work
 however. Most db's support optimistic locking, but not pessimistic
 locking.

 If you want to use this at the application level you will have to
 do
 it yourself. You could put a variable somewhere to track wether an
 object is being edited and base access restrictions off of that.
 However you have to be very carefull about making sure you don't
 get
 any deadlock or race conditions.

 I suggest you delve into database world and read about how other
 people have solved this problem.

 mvg,
 Jasper

 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
  Hello everyone,
 
  Within our struts web application in which we have
 edit-actions
within
 a user can be busy editing data in the form for several minutes.
 
  The problem is, if another user is also editing the data at the
  same
 time, one of the is eventually going to overwrite the changes of
 the
other and
 the other will have worked completely in vain. So my question
 would
  be
 whether there's some way to prevent this from happening, some kind
  of
lock
 down method for edit-actions? I think this problem is not
 uncommon,
   can
 someone give me a tip?
 
  thanks in advance
  Julian
 
  --
 
  Bis zu 70% Ihrer Onlinekosten sparen: GMX SmartSurfer!
Kostenlos downloaden: http://www.gmx.net/de/go/smartsurfer
 
  
 -
  To unsubscribe, e-mail: [EMAIL PROTECTED]
  For additional commands, e-mail: [EMAIL PROTECTED]
 

 -
 To unsubscribe, e-mail: [EMAIL PROTECTED]
 For additional commands, e-mail: [EMAIL PROTECTED]
   
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Re: Re: Re: Re: How to lock the access of methods within an action?

2006-05-30 Thread Miguel Galves 

Sure...

On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:



Hi Miguel,

thanks for the tip, is it possible to use this in a struts action which is
not thread save?

ciao 4 now
Julian

 Original-Nachricht 
Datum: Tue, 30 May 2006 09:28:36 -0300
Von: Miguel Galves [EMAIL PROTECTED]
An: Struts Users Mailing List user@struts.apache.org
Betreff: Re: Re: Re: How to lock the access of methods within an action?
#xA Julian,

 you can use the lock provided by Java 1.5 API...they are very simple to
 use.
 For istance, I use java.util.concurrent.Semaphore.
 The code above sho how to use it:
 private Semaphore sceneryLock = new Semaphore(1, true);

   public void removeScenery() throws Exception {

 try {
 sceneryLock.acquire();

  do your critical stuff here ...
 } catch (InterruptedException e) {

 } finally {
 sceneryLock.release();
 }
 }

 Hope it helps ...

 []s

 Miguel

 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
 
  thx
 
  hmm, where can I find it, is it part of Spring?
 
   Original-Nachricht 
  Datum: Tue, 30 May 2006 18:36:06 +0800
  Von: Lixin Chu [EMAIL PROTECTED]
  An: Struts Users Mailing List user@struts.apache.org
  Betreff: Re: Re: How to lock the access of methods within an action?
  #xA i think transaction manager will take care of this.
  
   On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
   
Thanks a lot for your answer!
   
My thinking behind is the application level!
   
I'm not sure but the goal is (my hope..)to solve
   
this problem using aspect oriented programming or Spring
   
although I'm not very aware of it.
   
For example it would be nice to have one central configuration
there
  you
   
can say:
   
this method -max-users 1-
   
rule: throw error ….
   
Should be done then a second users wants access to the method.
   
Can you help me?
   
Thanks a lot!
   
 Original-Nachricht 
Datum: Tue, 30 May 2006 10:55:17 +0200
Von: The Jasper [EMAIL PROTECTED]
An: Struts Users Mailing List user@struts.apache.org
Betreff: Re: How to lock the access of methods within an action?
#xA Hi,

 this sounds like a common database problem. You might want to
  consider
 some kind of pessimistic locking. Basically you lock the object
 when
 you start editing and prevent all access to it for the duration
of
  the
 lock. You could also do an optimistic lock which means that when
 you
 change an object it will only be committed if the object hasn't
 changed between the time you got your lock and the time you want
 to
 commit it. This doens't prevent you from having done unnecessary
  work
 however. Most db's support optimistic locking, but not
pessimistic
 locking.

 If you want to use this at the application level you will have
to
 do
 it yourself. You could put a variable somewhere to track wether
an
 object is being edited and base access restrictions off of that.
 However you have to be very carefull about making sure you don't
 get
 any deadlock or race conditions.

 I suggest you delve into database world and read about how other
 people have solved this problem.

 mvg,
 Jasper

 On 5/30/06, Julian Tillmann [EMAIL PROTECTED] wrote:
  Hello everyone,
 
  Within our struts web application in which we have
 edit-actions
within
 a user can be busy editing data in the form for several minutes.
 
  The problem is, if another user is also editing the data at
the
  same
 time, one of the is eventually going to overwrite the changes of
 the
other and
 the other will have worked completely in vain. So my question
 would
  be
 whether there's some way to prevent this from happening, some
kind
  of
lock
 down method for edit-actions? I think this problem is not
 uncommon,
   can
 someone give me a tip?
 
  thanks in advance
  Julian
 
  --
 
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Kostenlos downloaden:
http://www.gmx.net/de/go/smartsurfer
 
  
 -
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 For additional commands, e-mail: [EMAIL PROTECTED]
   
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