You are viewing a plain text version of this content. The canonical link for it is here.
Posted to users@tapestry.apache.org by Dave Rathnow <dr...@telus.net> on 2006/10/05 04:09:09 UTC
Newbie question about ApplicationServlet
I'm new to Tapestry and have just started working with it. My background is WebObjects so
most of my question will come from that perspective.
The application I'm developing will be doing some background processing with the UI providing
monitoring and control functions. In WebObjects, we would use an single Application instance
that is created when the web application is first started. We would store the objects required to
access and control the back ground processing. This Application instance is then available in
in each request-response loop through a Session object, or through a global static method.
Is this same model provided by the ApplicationServlet class in Tapestry? Is there a single instance
of this object and if so, how can I get it? Is it common practice to subclass this class and
then do all your own application specific logic in the derived class?
Thanks,
Dave.
NotSerializableException - MIME, Persist = client
Posted by Joel <jo...@harpsoft.com>.
I have a datasqueezer works fine when persisting as a link or value of a
radio button, however, if I try to persist="cllient" or client:page I
get an exception, NotSerializableException and its complaining about
MIME in some regard. The datasqueezer happens to return an ID that is in
the format of an URL.
Any ideas?
Joel
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: Newbie question about ApplicationServlet
Posted by Dave Rathnow <dr...@telus.net>.
Jessie,
I'm not sure what you're refering to. Do you mean creating threads or the
process
of initializing my background process, which may involve creating threads?
Dave.
----- Original Message -----
From: "Jesse Kuhnert" <jk...@gmail.com>
To: "Tapestry users" <us...@tapestry.apache.org>
Sent: Wednesday, October 04, 2006 11:25 PM
Subject: Re: Newbie question about ApplicationServlet
> Oh no... Don't do anything remotely like that.
>
> You want to go look at jakarta.apache.org/hivemind. It's a very powerful
> IoC
> container - and it's also what t4 is built on.
>
> You'll find almost any pattern (including thread per session ) available
> to
> you once you peek inside. Almost all of the core of Tapestry is broken up
> into easy to manage / inject services.
>
> On 10/4/06, Dennis Sinelnikov <de...@augustschell.com> wrote:
>>
>> Hello Dave,
>>
>> There is 1 instance of ApplicationServlet, with newer releases of
>> tapestry there is less and less things I can think of doing in the
>> ApplicationServlet. You can extend from
>> org.apache.tapestry.ApplicationServlet and create your own (perfectly ok
>> to do). In ApplicationServlet, usually you would do some global
>> configuration settings, resource allocation, fork threads, etc..
>>
>> Without knowing too much about the application you're trying to develop,
>> you could fork threads in your ApplicationServlet that would do your
>> background processing and just clean them up in destroy(). I would not
>> recommend getting your ApplicationServlet instance, but perhaps develop
>> separate logic that would get triggered via a UI. This logic would do
>> monitoring/control and return response to the user via a UI. If you
>> need some global object or perhaps one of the threads that got forked
>> upon ApplicationServlet startup, consider having a pool of threads that
>> have the same purpose that you can just grab at any point...
>>
>> Hope this helps,
>> Dennis
>>
>> Dave Rathnow wrote:
>> > I'm new to Tapestry and have just started working with it. My
>> background is WebObjects so
>> > most of my question will come from that perspective.
>> >
>> > The application I'm developing will be doing some background processing
>> with the UI providing
>> > monitoring and control functions. In WebObjects, we would use an
>> > single
>> Application instance
>> > that is created when the web application is first started. We would
>> store the objects required to
>> > access and control the back ground processing. This Application
>> instance is then available in
>> > in each request-response loop through a Session object, or through a
>> global static method.
>> >
>> > Is this same model provided by the ApplicationServlet class in
>> Tapestry? Is there a single instance
>> > of this object and if so, how can I get it? Is it common practice to
>> subclass this class and
>> > then do all your own application specific logic in the derived class?
>> >
>> > Thanks,
>> > Dave.
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
>> For additional commands, e-mail: users-help@tapestry.apache.org
>>
>>
>
>
> --
> Jesse Kuhnert
> Tapestry/Dojo/(and a dash of TestNG), team member/developer
>
> Open source based consulting work centered around
> dojo/tapestry/tacos/hivemind. http://blog.opencomponentry.com
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: Newbie question about ApplicationServlet
Posted by Jesse Kuhnert <jk...@gmail.com>.
Oh no... Don't do anything remotely like that.
You want to go look at jakarta.apache.org/hivemind. It's a very powerful IoC
container - and it's also what t4 is built on.
You'll find almost any pattern (including thread per session ) available to
you once you peek inside. Almost all of the core of Tapestry is broken up
into easy to manage / inject services.
On 10/4/06, Dennis Sinelnikov <de...@augustschell.com> wrote:
>
> Hello Dave,
>
> There is 1 instance of ApplicationServlet, with newer releases of
> tapestry there is less and less things I can think of doing in the
> ApplicationServlet. You can extend from
> org.apache.tapestry.ApplicationServlet and create your own (perfectly ok
> to do). In ApplicationServlet, usually you would do some global
> configuration settings, resource allocation, fork threads, etc..
>
> Without knowing too much about the application you're trying to develop,
> you could fork threads in your ApplicationServlet that would do your
> background processing and just clean them up in destroy(). I would not
> recommend getting your ApplicationServlet instance, but perhaps develop
> separate logic that would get triggered via a UI. This logic would do
> monitoring/control and return response to the user via a UI. If you
> need some global object or perhaps one of the threads that got forked
> upon ApplicationServlet startup, consider having a pool of threads that
> have the same purpose that you can just grab at any point...
>
> Hope this helps,
> Dennis
>
> Dave Rathnow wrote:
> > I'm new to Tapestry and have just started working with it. My
> background is WebObjects so
> > most of my question will come from that perspective.
> >
> > The application I'm developing will be doing some background processing
> with the UI providing
> > monitoring and control functions. In WebObjects, we would use an single
> Application instance
> > that is created when the web application is first started. We would
> store the objects required to
> > access and control the back ground processing. This Application
> instance is then available in
> > in each request-response loop through a Session object, or through a
> global static method.
> >
> > Is this same model provided by the ApplicationServlet class in
> Tapestry? Is there a single instance
> > of this object and if so, how can I get it? Is it common practice to
> subclass this class and
> > then do all your own application specific logic in the derived class?
> >
> > Thanks,
> > Dave.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
>
--
Jesse Kuhnert
Tapestry/Dojo/(and a dash of TestNG), team member/developer
Open source based consulting work centered around
dojo/tapestry/tacos/hivemind. http://blog.opencomponentry.com
Re: Newbie question about ApplicationServlet
Posted by Steve Shucker <ss...@vmsinfo.com>.
First of all, if you want a single manager object, tapestry provides
Application State Objects to do this. See
http://tapestry.apache.org/tapestry4/UsersGuide/state.html#state.aso for
more info. For a single instance of an ASO across an entire
application, you set the scope to "application" instead of "session".
This is tapestry's preferred way of doing things, but the problem is
that (I think) it's lazily initialized.
JMS: Check out spring (http://www.springframework.org). They've had JMS
send capabilities for a while now and I've (lightly) used them
successfully. Spring 2.0 was released earlier this week and now has
Message Driven POJOs (MDPs) - the receiver side of JMS. It sets up a
pool of asynchronous receivers for you
(http://static.springframework.org/spring/docs/2.0.x/reference/jms.html).
A coworker of mine is starting to play with these and we're optimistic
that it'll eliminate our last reason to use an EJB container. If you're
using Spring, they provide a servlet filter that you can configure in
your web.xml to load the spring context when the app initializes. I
know I'm contradicting my first paragraph, but a spring context is also
a great place to construct your manager object and JMS config - no
worries about lazy initialization here.
Threads are messy and really hard to get right. This isn't specific to
servlets, just in general. That's why many people try to avoid them.
Personally, I'm more comfortable with a well-tested library to manage
threads for me.
Tapestry does a lot of things right, but it sounds like a good chunk of
your project is better covered by Spring's problem domain. Fortunately,
they play nice together.
-Steve
Dave Rathnow wrote:
> Hi Dennis,
>
> The application we're writing is "bridging" topics across multiple JMS
> servers. The
> initialization involves creating and initializing all the necessary
> JMS objects. Pretty
> simple, really, which is why we decided to make this our first
> Tapestry project.
>
> There is a single "manager" object that manages the bridge, which is
> being managed by
> the UI. The manger object has to be created at application startup
> time so I can't
> rely on any UI events to do this process for me. Right now, I've
> created my own
> ApplicationServlet subclass to handle this process. I'm using async
> message delivery
> so all the thread creation is being handle by the JMS implementation,
> except for some
> threads I create to handle connection loss events.
>
> I'm curious about handling threads inside a servlet. I know this is a
> bit off topic
> but, are there any problems with simply creating your own threads
> inside a servlet
> container or is there some magic that has to be done to ensure you
> don't mess
> things up? I've heard from a couple of people that there could be
> problems with
> managing your own threads. Is there any truth to this?
>
> Thanks,
> Dave.
>
> ----- Original Message ----- From: "Dennis Sinelnikov"
> <de...@augustschell.com>
> To: <us...@tapestry.apache.org>
> Sent: Wednesday, October 04, 2006 9:14 PM
> Subject: Re: Newbie question about ApplicationServlet
>
>
>> Hello Dave,
>>
>> There is 1 instance of ApplicationServlet, with newer releases of
>> tapestry there is less and less things I can think of doing in the
>> ApplicationServlet. You can extend from
>> org.apache.tapestry.ApplicationServlet and create your own (perfectly
>> ok to do). In ApplicationServlet, usually you would do some global
>> configuration settings, resource allocation, fork threads, etc..
>>
>> Without knowing too much about the application you're trying to
>> develop, you could fork threads in your ApplicationServlet that would
>> do your background processing and just clean them up in destroy(). I
>> would not recommend getting your ApplicationServlet instance, but
>> perhaps develop separate logic that would get triggered via a UI.
>> This logic would do monitoring/control and return response to the
>> user via a UI. If you need some global object or perhaps one of the
>> threads that got forked upon ApplicationServlet startup, consider
>> having a pool of threads that have the same purpose that you can just
>> grab at any point...
>>
>> Hope this helps,
>> Dennis
>>
>> Dave Rathnow wrote:
>>> I'm new to Tapestry and have just started working with it. My
>>> background is WebObjects so
>>> most of my question will come from that perspective.
>>>
>>> The application I'm developing will be doing some background
>>> processing with the UI providing
>>> monitoring and control functions. In WebObjects, we would use an
>>> single Application instance that is created when the web application
>>> is first started. We would store the objects required to access and
>>> control the back ground processing. This Application instance is
>>> then available in
>>> in each request-response loop through a Session object, or through a
>>> global static method.
>>>
>>> Is this same model provided by the ApplicationServlet class in
>>> Tapestry? Is there a single instance
>>> of this object and if so, how can I get it? Is it common practice
>>> to subclass this class and
>>> then do all your own application specific logic in the derived class?
>>>
>>> Thanks,
>>> Dave.
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
>> For additional commands, e-mail: users-help@tapestry.apache.org
>>
>>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: Newbie question about ApplicationServlet
Posted by Dennis Sinelnikov <de...@augustschell.com>.
Dave,
In Tapestry3, we have a web application that forks our custom threads,
nothing wrong with that. Jesse is right with Tapestry4, HiveMind does
many neat things for you. I've only had a chance to play around parsing
application configurations via a xml file. HiveMind would basically
parse xml data and create java objects for me using specified
rules/schema.
I'm not a HiveMind expert, but I believe ApplicationServlet reads all of
tapestry's HiveMind registries (simple xml files) upon start up. So you
can write your own xml file using HiveMind APIs, that would get parsed
upon ApplicationServlet start up and access your "services" whenever you
want in your app. Check out http://jakarta.apache.org/hivemind/ , there
is a lot of useful information and code examples there...
Good Luck,
Dennis
Dave Rathnow wrote:
> Hi Dennis,
>
> The application we're writing is "bridging" topics across multiple JMS
> servers. The
> initialization involves creating and initializing all the necessary JMS
> objects. Pretty
> simple, really, which is why we decided to make this our first Tapestry
> project.
>
> There is a single "manager" object that manages the bridge, which is
> being managed by
> the UI. The manger object has to be created at application startup time
> so I can't
> rely on any UI events to do this process for me. Right now, I've
> created my own
> ApplicationServlet subclass to handle this process. I'm using async
> message delivery
> so all the thread creation is being handle by the JMS implementation,
> except for some
> threads I create to handle connection loss events.
>
> I'm curious about handling threads inside a servlet. I know this is a
> bit off topic
> but, are there any problems with simply creating your own threads inside
> a servlet
> container or is there some magic that has to be done to ensure you don't
> mess
> things up? I've heard from a couple of people that there could be
> problems with
> managing your own threads. Is there any truth to this?
>
> Thanks,
> Dave.
>
> ----- Original Message ----- From: "Dennis Sinelnikov"
> <de...@augustschell.com>
> To: <us...@tapestry.apache.org>
> Sent: Wednesday, October 04, 2006 9:14 PM
> Subject: Re: Newbie question about ApplicationServlet
>
>
>> Hello Dave,
>>
>> There is 1 instance of ApplicationServlet, with newer releases of
>> tapestry there is less and less things I can think of doing in the
>> ApplicationServlet. You can extend from
>> org.apache.tapestry.ApplicationServlet and create your own (perfectly
>> ok to do). In ApplicationServlet, usually you would do some global
>> configuration settings, resource allocation, fork threads, etc..
>>
>> Without knowing too much about the application you're trying to
>> develop, you could fork threads in your ApplicationServlet that would
>> do your background processing and just clean them up in destroy(). I
>> would not recommend getting your ApplicationServlet instance, but
>> perhaps develop separate logic that would get triggered via a UI.
>> This logic would do monitoring/control and return response to the user
>> via a UI. If you need some global object or perhaps one of the
>> threads that got forked upon ApplicationServlet startup, consider
>> having a pool of threads that have the same purpose that you can just
>> grab at any point...
>>
>> Hope this helps,
>> Dennis
>>
>> Dave Rathnow wrote:
>>> I'm new to Tapestry and have just started working with it. My
>>> background is WebObjects so
>>> most of my question will come from that perspective.
>>>
>>> The application I'm developing will be doing some background
>>> processing with the UI providing
>>> monitoring and control functions. In WebObjects, we would use an
>>> single Application instance that is created when the web application
>>> is first started. We would store the objects required to access and
>>> control the back ground processing. This Application instance is
>>> then available in
>>> in each request-response loop through a Session object, or through a
>>> global static method.
>>>
>>> Is this same model provided by the ApplicationServlet class in
>>> Tapestry? Is there a single instance
>>> of this object and if so, how can I get it? Is it common practice to
>>> subclass this class and
>>> then do all your own application specific logic in the derived class?
>>>
>>> Thanks,
>>> Dave.
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
>> For additional commands, e-mail: users-help@tapestry.apache.org
>>
>>
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: Newbie question about ApplicationServlet
Posted by Dave Rathnow <dr...@telus.net>.
Hi Dennis,
The application we're writing is "bridging" topics across multiple JMS
servers. The
initialization involves creating and initializing all the necessary JMS
objects. Pretty
simple, really, which is why we decided to make this our first Tapestry
project.
There is a single "manager" object that manages the bridge, which is being
managed by
the UI. The manger object has to be created at application startup time so
I can't
rely on any UI events to do this process for me. Right now, I've created my
own
ApplicationServlet subclass to handle this process. I'm using async message
delivery
so all the thread creation is being handle by the JMS implementation, except
for some
threads I create to handle connection loss events.
I'm curious about handling threads inside a servlet. I know this is a bit
off topic
but, are there any problems with simply creating your own threads inside a
servlet
container or is there some magic that has to be done to ensure you don't
mess
things up? I've heard from a couple of people that there could be problems
with
managing your own threads. Is there any truth to this?
Thanks,
Dave.
----- Original Message -----
From: "Dennis Sinelnikov" <de...@augustschell.com>
To: <us...@tapestry.apache.org>
Sent: Wednesday, October 04, 2006 9:14 PM
Subject: Re: Newbie question about ApplicationServlet
> Hello Dave,
>
> There is 1 instance of ApplicationServlet, with newer releases of tapestry
> there is less and less things I can think of doing in the
> ApplicationServlet. You can extend from
> org.apache.tapestry.ApplicationServlet and create your own (perfectly ok
> to do). In ApplicationServlet, usually you would do some global
> configuration settings, resource allocation, fork threads, etc..
>
> Without knowing too much about the application you're trying to develop,
> you could fork threads in your ApplicationServlet that would do your
> background processing and just clean them up in destroy(). I would not
> recommend getting your ApplicationServlet instance, but perhaps develop
> separate logic that would get triggered via a UI. This logic would do
> monitoring/control and return response to the user via a UI. If you need
> some global object or perhaps one of the threads that got forked upon
> ApplicationServlet startup, consider having a pool of threads that have
> the same purpose that you can just grab at any point...
>
> Hope this helps,
> Dennis
>
> Dave Rathnow wrote:
>> I'm new to Tapestry and have just started working with it. My background
>> is WebObjects so
>> most of my question will come from that perspective.
>>
>> The application I'm developing will be doing some background processing
>> with the UI providing
>> monitoring and control functions. In WebObjects, we would use an single
>> Application instance that is created when the web application is first
>> started. We would store the objects required to access and control the
>> back ground processing. This Application instance is then available in
>> in each request-response loop through a Session object, or through a
>> global static method.
>>
>> Is this same model provided by the ApplicationServlet class in Tapestry?
>> Is there a single instance
>> of this object and if so, how can I get it? Is it common practice to
>> subclass this class and
>> then do all your own application specific logic in the derived class?
>>
>> Thanks,
>> Dave.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org
Re: Newbie question about ApplicationServlet
Posted by Dennis Sinelnikov <de...@augustschell.com>.
Hello Dave,
There is 1 instance of ApplicationServlet, with newer releases of
tapestry there is less and less things I can think of doing in the
ApplicationServlet. You can extend from
org.apache.tapestry.ApplicationServlet and create your own (perfectly ok
to do). In ApplicationServlet, usually you would do some global
configuration settings, resource allocation, fork threads, etc..
Without knowing too much about the application you're trying to develop,
you could fork threads in your ApplicationServlet that would do your
background processing and just clean them up in destroy(). I would not
recommend getting your ApplicationServlet instance, but perhaps develop
separate logic that would get triggered via a UI. This logic would do
monitoring/control and return response to the user via a UI. If you
need some global object or perhaps one of the threads that got forked
upon ApplicationServlet startup, consider having a pool of threads that
have the same purpose that you can just grab at any point...
Hope this helps,
Dennis
Dave Rathnow wrote:
> I'm new to Tapestry and have just started working with it. My background is WebObjects so
> most of my question will come from that perspective.
>
> The application I'm developing will be doing some background processing with the UI providing
> monitoring and control functions. In WebObjects, we would use an single Application instance
> that is created when the web application is first started. We would store the objects required to
> access and control the back ground processing. This Application instance is then available in
> in each request-response loop through a Session object, or through a global static method.
>
> Is this same model provided by the ApplicationServlet class in Tapestry? Is there a single instance
> of this object and if so, how can I get it? Is it common practice to subclass this class and
> then do all your own application specific logic in the derived class?
>
> Thanks,
> Dave.
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
For additional commands, e-mail: users-help@tapestry.apache.org