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Posted to user@struts.apache.org by "Asleson, Ryan" <as...@BIWORLDWIDE.com> on 2008/06/23 15:35:57 UTC
Struts 2: Providing Tiles Controller-like Functionality
Hello,
We're moving from a Struts 1.x with Tiles development model to Struts 2
and Sitemesh.
One thing we miss with from Tiles is the ability to back a JSP with a
Controller. The Controller guaranteed that whenever a JSP was rendered,
certain behavior was executed to prepare data for the JSP. For example,
the loading of data for drop-down select boxes was often placed in the
Controller.
Now that we're not using Tiles we can no longer use Controllers, so I'm
wondering if Struts 2 has any sort of equivalent functionality. I'm
familiar with the Struts 2 Preparable interface, but I don't like this
because prepare() is always called -- even on form posts, which in my
case, is at best an unnecessary database hit (or hits), and at worst can
cause confusion with what was actually posted from the page vs. what was
retrieved from prepare().
If it helps any, we have a 1:1 mapping between an Action and a JSP,
including a naming convention: MyFavoriteAction maps to myFavorite.jsp.
Any thoughts or comments?
Thank you!!
-Ryan
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RE: Struts 2: Providing Tiles Controller-like Functionality
Posted by Brad A Cupit <br...@lsu.edu>.
Asleson, Ryan wrote:
> I've thought about writing a PreResultListener
<snip/>
> I've tried ActionInvocation.getResult(), but it only returns null.
> Is there a way to get the current Result object before it is
> actually executed?
Looking at the code for DefaultActionInvocation, it seems that
createResult() only gets called in executeResult().
If the your add() or remove() methods return an instance of a Result
(instead of a String) then I would guess that
ActionInvocation.getResult() would return what you expect, though
returning a instance of Result may not fit your needs.
What's strange is the documentation for
DefaultActionInvocation.getResult(), which says:
"If the DefaultActionInvocation's result has not been executed before,
the Result instance will be created and populated with the result
params."
The code in DefaultActionInvocation.getResult() doesn't seem to do that
functionality though (and the fact that ActionInvocation.getResult()
returns null seems like proof).
An extremely hacky workaround _may_ be to cast your ActionInvocation to
DefaultActionInvocation and then call the public createResult() method
(though createResult() will be called twice if you do that: once by you
and once by executeResult()).
With a little more digging, you may be able to prove that this is a bug
in Struts 2.
Having said all that, can I backtrack for a second and ask if the
following would solve your problem:
Could you implement Preparable and have an empty prepare() method, plus
prepareAdd() and prepareRemove() methods, each with preparation logic
specific to add() and remove(), respectively?
Brad Cupit
Louisiana State University - UIS
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RE: Struts 2: Providing Tiles Controller-like Functionality
Posted by "Asleson, Ryan" <as...@BIWORLDWIDE.com>.
Thank you for your thoughts!
Our model is to use one Action per JSP. So, for example, if a JSP has
Add and Remove buttons, the Action has corresponding add() and remove()
methods. We use this model because it cuts down on the proliferation of
Action classes.
Yes, Preparable is nice because it gets called even when validation
errors occur, which is functionality we need.
I've thought about writing a PreResultListener that checks the Result
for the desired destination. If the destination (say, myFavorite.jsp)
matches the Action (MyFavoriteAction.class) then run the prepare method.
However, I can't find a way to get the current Result. I've tried
ActionInvocation.getResult(), but it only returns null. Is there a way
to get the current Result object before it is actually executed? This
would help greatly.
Any other thoughts are greatly appreciated.
-Ryan
-----Original Message-----
From: Brad A Cupit [mailto:brad@lsu.edu]
Sent: Monday, June 23, 2008 10:19 AM
To: Struts Users Mailing List
Subject: RE: Struts 2: Providing Tiles Controller-like Functionality
Asleson, Ryan wrote:
> I'm familiar with the Struts 2 Preparable interface, but I don't like
> this because prepare() is always called -- even on form posts
Do you have one Action with two public methods that are called by Struts
2? For example view() and submit() methods? If that's the case, I can
understand why you wouldn't want prepare() called when submit() is
called.
To solve that, just rename your prepare method to prepareView(), and it
will only run when view() is called.
If you are not using multiple public methods in one Action, and each
Action just implements the execute() method, I'd assume you have
separate Actions for viewing and submitting, let's call them ViewAction
and SubmitAction.
In this situation, make your ViewAction implement Preparable, but don't
have SubmitAction implement it.
Am I way off base here?
I personally like Preparable since the method gets called even when
there is a validation error. So you have a place to put code that you
want run both on initial display and on after a POST with validation
errors.
Brad Cupit
Louisiana State University - UIS
-----Original Message-----
From: Asleson, Ryan [mailto:asleson@BIWORLDWIDE.com]
Sent: Monday, June 23, 2008 8:36 AM
To: Struts Users Mailing List
Subject: Struts 2: Providing Tiles Controller-like Functionality
Hello,
We're moving from a Struts 1.x with Tiles development model to Struts 2
and Sitemesh.
One thing we miss with from Tiles is the ability to back a JSP with a
Controller. The Controller guaranteed that whenever a JSP was rendered,
certain behavior was executed to prepare data for the JSP. For example,
the loading of data for drop-down select boxes was often placed in the
Controller.
Now that we're not using Tiles we can no longer use Controllers, so I'm
wondering if Struts 2 has any sort of equivalent functionality. I'm
familiar with the Struts 2 Preparable interface, but I don't like this
because prepare() is always called -- even on form posts, which in my
case, is at best an unnecessary database hit (or hits), and at worst can
cause confusion with what was actually posted from the page vs. what was
retrieved from prepare().
If it helps any, we have a 1:1 mapping between an Action and a JSP,
including a naming convention: MyFavoriteAction maps to myFavorite.jsp.
Any thoughts or comments?
Thank you!!
-Ryan
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the intended recipient, please contact the sender by phone or reply by
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RE: Struts 2: Providing Tiles Controller-like Functionality
Posted by Brad A Cupit <br...@lsu.edu>.
Asleson, Ryan wrote:
> I'm familiar with the Struts 2 Preparable interface, but I don't
> like this because prepare() is always called -- even on form posts
Do you have one Action with two public methods that are called by Struts
2? For example view() and submit() methods? If that's the case, I can
understand why you wouldn't want prepare() called when submit() is
called.
To solve that, just rename your prepare method to prepareView(), and it
will only run when view() is called.
If you are not using multiple public methods in one Action, and each
Action just implements the execute() method, I'd assume you have
separate Actions for viewing and submitting, let's call them ViewAction
and SubmitAction.
In this situation, make your ViewAction implement Preparable, but don't
have SubmitAction implement it.
Am I way off base here?
I personally like Preparable since the method gets called even when
there is a validation error. So you have a place to put code that you
want run both on initial display and on after a POST with validation
errors.
Brad Cupit
Louisiana State University - UIS
-----Original Message-----
From: Asleson, Ryan [mailto:asleson@BIWORLDWIDE.com]
Sent: Monday, June 23, 2008 8:36 AM
To: Struts Users Mailing List
Subject: Struts 2: Providing Tiles Controller-like Functionality
Hello,
We're moving from a Struts 1.x with Tiles development model to Struts 2
and Sitemesh.
One thing we miss with from Tiles is the ability to back a JSP with a
Controller. The Controller guaranteed that whenever a JSP was rendered,
certain behavior was executed to prepare data for the JSP. For example,
the loading of data for drop-down select boxes was often placed in the
Controller.
Now that we're not using Tiles we can no longer use Controllers, so I'm
wondering if Struts 2 has any sort of equivalent functionality. I'm
familiar with the Struts 2 Preparable interface, but I don't like this
because prepare() is always called -- even on form posts, which in my
case, is at best an unnecessary database hit (or hits), and at worst can
cause confusion with what was actually posted from the page vs. what was
retrieved from prepare().
If it helps any, we have a 1:1 mapping between an Action and a JSP,
including a naming convention: MyFavoriteAction maps to myFavorite.jsp.
Any thoughts or comments?
Thank you!!
-Ryan
This e-mail message is being sent solely for use by the intended
recipient(s) and may contain confidential information. Any unauthorized
review, use, disclosure or distribution is prohibited. If you are not
the intended recipient, please contact the sender by phone or reply by
e-mail, delete the original message and destroy all copies. Thank you.
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Re: Struts 2: Providing Tiles Controller-like Functionality
Posted by Antonio Petrelli <an...@gmail.com>.
2008/6/23 Asleson, Ryan <as...@biworldwide.com>:
> One thing we miss with from Tiles is the ability to back a JSP with a
> Controller. The Controller guaranteed that whenever a JSP was rendered,
> certain behavior was executed to prepare data for the JSP. For example,
> the loading of data for drop-down select boxes was often placed in the
> Controller.
>
> Now that we're not using Tiles we can no longer use Controllers
Well, Tiles 1 "controllers" were renamed to "view preparers" in Tiles 2. See:
http://tiles.apache.org/tutorial/advanced/preparer.html
Ciao
Antonio
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