Destroy an Action in Struts2?

[JOSE L MARTINEZ-AVIAL <jl...@gmail.com>]

Hi,
   Is there a way to destroy correctly an Action? I know that a instance of
an Action is created every time it is needed, and it is alive during the
processing of the request until the response is sent back to the user. What
I don't know is if the instance is 'destroyed' in some way, or Struts just
sets to null the references to it, and that's it. I'm used to implement a
Destroyable interface in all my classes, which I use to clear any Map, List,
etc, and set to null any field in the object, in order to avoid memory
leaks. I would like to do the same with the action. I know I could implement
an Interceptor to do that, but I don't know if this is already covered in
Struts. Any thoughts?

TIA

Jose Luis

Re: Destroy an Action in Struts2?

[JOSE L MARTINEZ-AVIAL <jl...@gmail.com>]

Well, I don't have an issue with memory leaks now, and it's been a while
since I had some problem with it(but it was due to some references in a list
not cleaned).. It maybe a 'cargo cult', but I don't think it is
harmful,-apart from some overhead- so I just prefer to be on the safe side.

A little OT. If I recall correctly, the GC basically keeps a count of the
references for each object in the JVM. Once the number of refereces is null,
it cleans the object. But let's say we have a circular reference between two
objects, and we clean any references to them. What would happen with those
objects? Will they be cleaned?

JL

2011/8/1 Dave Newton <da...@gmail.com>

> Unless you have proof an action's properties are causing a memory leak, it
> sounds like "cargo cult" programming to me. Most cases if leaks like this
> are caused by something else in the code keeping references.
>
> Have you profiled the app to see if what you want is really necessary? I'm
> pretty skeptical.
>
> Dave
>  On Aug 1, 2011 3:49 AM, "JOSE L MARTINEZ-AVIAL" <jl...@gmail.com> wrote:
> > Well, the interceptor should be the first one on the stack, so all data
> > required in the result should have been already used. It's not a bad
> idea,
> I
> > will work with that.
> >
> > With respect to the GC, back in 2002 when I started using Java the GC
> didn't
> > work quite well, and my team and I started clearing and setting to null
> any
> > reference that weren't used anymore to avoid issues with memory, and I've
> > doing that since then. In fact, the few times I've had some issues with
> > memory leaks, it was usually due to some variables fields not cleared.
> >
> > 2011/8/1 Maurizio Cucchiara <mc...@apache.org>
> >
> >> Doing what you are looking for through an interceptor is quite
> >> trivial: you should simply check (after the invocation.invoke() call)
> >> if an action implements Destroyable IF and then call the destroy
> >> method.
> >> Anyway, I think that the garbage collector in this specific case is
> >> able to do a good work, why don't you trust it?
> >>
> >> On 1 August 2011 08:44, JOSE L MARTINEZ-AVIAL <jl...@gmail.com> wrote:
> >> > Hi,
> >> > Is there a way to destroy correctly an Action? I know that a instance
> >> of
> >> > an Action is created every time it is needed, and it is alive during
> the
> >> > processing of the request until the response is sent back to the user.
> >> What
> >> > I don't know is if the instance is 'destroyed' in some way, or Struts
> >> just
> >> > sets to null the references to it, and that's it. I'm used to
> implement
> a
> >> > Destroyable interface in all my classes, which I use to clear any Map,
> >> List,
> >> > etc, and set to null any field in the object, in order to avoid memory
> >> > leaks. I would like to do the same with the action. I know I could
> >> implement
> >> > an Interceptor to do that, but I don't know if this is already covered
> in
> >> > Struts. Any thoughts?
> >> >
> >> > TIA
> >> >
> >> > Jose Luis
> >> >
> >>
> >>
> >>
> >> --
> >> Maurizio Cucchiara
> >>
> >> ---------------------------------------------------------------------
> >> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> >> For additional commands, e-mail: user-help@struts.apache.org
> >>
> >>
>

Re: Destroy an Action in Struts2?

[Dave Newton <da...@gmail.com>]

Unless you have proof an action's properties are causing a memory leak, it
sounds like "cargo cult" programming to me. Most cases if leaks like this
are caused by something else in the code keeping references.

Have you profiled the app to see if what you want is really necessary? I'm
pretty skeptical.

Dave
 On Aug 1, 2011 3:49 AM, "JOSE L MARTINEZ-AVIAL" <jl...@gmail.com> wrote:
> Well, the interceptor should be the first one on the stack, so all data
> required in the result should have been already used. It's not a bad idea,
I
> will work with that.
>
> With respect to the GC, back in 2002 when I started using Java the GC
didn't
> work quite well, and my team and I started clearing and setting to null
any
> reference that weren't used anymore to avoid issues with memory, and I've
> doing that since then. In fact, the few times I've had some issues with
> memory leaks, it was usually due to some variables fields not cleared.
>
> 2011/8/1 Maurizio Cucchiara <mc...@apache.org>
>
>> Doing what you are looking for through an interceptor is quite
>> trivial: you should simply check (after the invocation.invoke() call)
>> if an action implements Destroyable IF and then call the destroy
>> method.
>> Anyway, I think that the garbage collector in this specific case is
>> able to do a good work, why don't you trust it?
>>
>> On 1 August 2011 08:44, JOSE L MARTINEZ-AVIAL <jl...@gmail.com> wrote:
>> > Hi,
>> > Is there a way to destroy correctly an Action? I know that a instance
>> of
>> > an Action is created every time it is needed, and it is alive during
the
>> > processing of the request until the response is sent back to the user.
>> What
>> > I don't know is if the instance is 'destroyed' in some way, or Struts
>> just
>> > sets to null the references to it, and that's it. I'm used to implement
a
>> > Destroyable interface in all my classes, which I use to clear any Map,
>> List,
>> > etc, and set to null any field in the object, in order to avoid memory
>> > leaks. I would like to do the same with the action. I know I could
>> implement
>> > an Interceptor to do that, but I don't know if this is already covered
in
>> > Struts. Any thoughts?
>> >
>> > TIA
>> >
>> > Jose Luis
>> >
>>
>>
>>
>> --
>> Maurizio Cucchiara
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>> For additional commands, e-mail: user-help@struts.apache.org
>>
>>

Re: Destroy an Action in Struts2?

[JOSE L MARTINEZ-AVIAL <jl...@gmail.com>]

Well, the interceptor should be the first one on the stack, so all data
required in the result should have been already used. It's not a bad idea, I
will work with that.

With respect to the GC, back in 2002 when I started using Java the GC didn't
work quite well, and my team and I started clearing and setting to null any
reference that weren't used anymore to avoid issues with memory, and I've
doing that since then. In fact, the few times I've had some issues with
memory leaks, it was usually due to some variables fields not cleared.

2011/8/1 Maurizio Cucchiara <mc...@apache.org>

> Doing what you are looking for through an interceptor is quite
> trivial: you should simply check  (after the invocation.invoke() call)
> if an action implements Destroyable IF and then call the destroy
> method.
> Anyway, I think that the garbage collector in this specific case is
> able to do a good work, why don't you trust it?
>
> On 1 August 2011 08:44, JOSE L MARTINEZ-AVIAL <jl...@gmail.com> wrote:
> > Hi,
> >   Is there a way to destroy correctly an Action? I know that a instance
> of
> > an Action is created every time it is needed, and it is alive during the
> > processing of the request until the response is sent back to the user.
> What
> > I don't know is if the instance is 'destroyed' in some way, or Struts
> just
> > sets to null the references to it, and that's it. I'm used to implement a
> > Destroyable interface in all my classes, which I use to clear any Map,
> List,
> > etc, and set to null any field in the object, in order to avoid memory
> > leaks. I would like to do the same with the action. I know I could
> implement
> > an Interceptor to do that, but I don't know if this is already covered in
> > Struts. Any thoughts?
> >
> > TIA
> >
> > Jose Luis
> >
>
>
>
> --
> Maurizio Cucchiara
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> For additional commands, e-mail: user-help@struts.apache.org
>
>

Re: Destroy an Action in Struts2?

[Maurizio Cucchiara <mc...@apache.org>]

Doing what you are looking for through an interceptor is quite
trivial: you should simply check  (after the invocation.invoke() call)
if an action implements Destroyable IF and then call the destroy
method.
Anyway, I think that the garbage collector in this specific case is
able to do a good work, why don't you trust it?

On 1 August 2011 08:44, JOSE L MARTINEZ-AVIAL <jl...@gmail.com> wrote:
> Hi,
>   Is there a way to destroy correctly an Action? I know that a instance of
> an Action is created every time it is needed, and it is alive during the
> processing of the request until the response is sent back to the user. What
> I don't know is if the instance is 'destroyed' in some way, or Struts just
> sets to null the references to it, and that's it. I'm used to implement a
> Destroyable interface in all my classes, which I use to clear any Map, List,
> etc, and set to null any field in the object, in order to avoid memory
> leaks. I would like to do the same with the action. I know I could implement
> an Interceptor to do that, but I don't know if this is already covered in
> Struts. Any thoughts?
>
> TIA
>
> Jose Luis
>



-- 
Maurizio Cucchiara

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