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Posted to user@struts.apache.org by Eric Lentz <Er...@sherwin.com> on 2011/04/26 21:52:45 UTC
Field Name Collision?
- Struts 2.2.1
- Tomcat 6.0
- JDK 1.5.0_22
- Code example of the problem: http://pastebin.com/eyyJaBg4
- Description:
I have two fields in my action class: user and userId. The user variable
is of type User, which also contains a userId. In both cases userId is of
type String.
While implementing SessionAware and ModelDriven...
Happy path:
If I pass a parameter in the URL as follows:
http://localhost:8080/Context/test-list.action?user.userId=foo
Then user.userId = "foo" when it gets to the action.
Not-so-happy path:
If I pass a parameter in the URL as follows:
http://localhost:8080/Context/test-list.action?userId=foo
Then user.userId = "foo" when it gets to the action.
Note that in both cases, "foo" was assigned to user.userId, though I used
different keys in the URL each time!
- Work-around:
If I change either one of the names to something that is unique to the
other, then it works as one would expect.
Am I doing something wrong?
- Eric
Re: Field Name Collision?
Posted by Chris Mawata <ch...@mathcove.net>.
That is how OGNL works -- the Model object is higher and has a property
of the name userId so it is the first match.
Chris
On 4/26/2011 3:52 PM, Eric Lentz wrote:
> - Struts 2.2.1
> - Tomcat 6.0
> - JDK 1.5.0_22
> - Code example of the problem: http://pastebin.com/eyyJaBg4
> - Description:
> I have two fields in my action class: user and userId. The user variable
> is of type User, which also contains a userId. In both cases userId is of
> type String.
>
> While implementing SessionAware and ModelDriven...
>
> Happy path:
> If I pass a parameter in the URL as follows:
> http://localhost:8080/Context/test-list.action?user.userId=foo
>
> Then user.userId = "foo" when it gets to the action.
>
> Not-so-happy path:
> If I pass a parameter in the URL as follows:
> http://localhost:8080/Context/test-list.action?userId=foo
>
> Then user.userId = "foo" when it gets to the action.
>
> Note that in both cases, "foo" was assigned to user.userId, though I used
> different keys in the URL each time!
>
> - Work-around:
> If I change either one of the names to something that is unique to the
> other, then it works as one would expect.
>
> Am I doing something wrong?
>
> - Eric
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Re: Field Name Collision?
Posted by Eric Lentz <Er...@sherwin.com>.
> - Struts instantiates the User object (in my case) by default.
> - ModelDriven places the object I choose at the top of the stack.
> - Because my object is at the top of the stack, it gets selected instead
> of the object that Struts creates by default.
I think I answered my own questions here stepping though the code. I don't
think Struts is instantiating unless it needs to. Thanks for the answers.
I think I see how this is all working now. I'm not sure how I feel about
it, but at least I understand.
- Eric
Re: Field Name Collision?
Posted by Eric Lentz <Er...@sherwin.com>.
> I don't use ModelDriven myself, but as I understand it, it places the
Model
> Object at the top of the Value Stack, which would make userid be a
reference
> to an attribute in the Model Object, not in the Action. When you use
> user.userid, it's because it's trying to find the user attribute in the
> Model Object (on the top of the Value Stack), which fails so it goes a
step
> down the stack to the Action, where it finds a user attribute to use.
>
> So, it appears Struts is functioning exactly as designed.
> (*Chris*)
Thanks for the explanation.
Are these correct statements about how Struts and ModelDriven works?
- Struts instantiates the User object (in my case) by default.
- ModelDriven places the object I choose at the top of the stack.
- Because my object is at the top of the stack, it gets selected instead
of the object that Struts creates by default.
- Eric
Re: Field Name Collision?
Posted by Dave Newton <da...@gmail.com>.
Oh, duh!
On Apr 26, 2011 4:20 PM, "Chris Pratt" <th...@gmail.com> wrote:
> I don't use ModelDriven myself, but as I understand it, it places the
Model
> Object at the top of the Value Stack, which would make userid be a
reference
> to an attribute in the Model Object, not in the Action. When you use
> user.userid, it's because it's trying to find the user attribute in the
> Model Object (on the top of the Value Stack), which fails so it goes a
step
> down the stack to the Action, where it finds a user attribute to use.
>
> So, it appears Struts is functioning exactly as designed.
> (*Chris*)
>
> On Tue, Apr 26, 2011 at 12:55 PM, Dave Newton <da...@gmail.com>
wrote:
>
>> Doubt you're doing anything wrong; I'd expect it's how OGNL does its
>> lookup but haven't confirmed that.
>>
>> Dave
>>
>> On Tue, Apr 26, 2011 at 3:52 PM, Eric Lentz <Er...@sherwin.com>
>> wrote:
>> > - Struts 2.2.1
>> > - Tomcat 6.0
>> > - JDK 1.5.0_22
>> > - Code example of the problem: http://pastebin.com/eyyJaBg4
>> > - Description:
>> > I have two fields in my action class: user and userId. The user
variable
>> > is of type User, which also contains a userId. In both cases userId is
of
>> > type String.
>> >
>> > While implementing SessionAware and ModelDriven...
>> >
>> > Happy path:
>> > If I pass a parameter in the URL as follows:
>> > http://localhost:8080/Context/test-list.action?user.userId=foo
>> >
>> > Then user.userId = "foo" when it gets to the action.
>> >
>> > Not-so-happy path:
>> > If I pass a parameter in the URL as follows:
>> > http://localhost:8080/Context/test-list.action?userId=foo
>> >
>> > Then user.userId = "foo" when it gets to the action.
>> >
>> > Note that in both cases, "foo" was assigned to user.userId, though I
used
>> > different keys in the URL each time!
>> >
>> > - Work-around:
>> > If I change either one of the names to something that is unique to the
>> > other, then it works as one would expect.
>> >
>> > Am I doing something wrong?
>> >
>> > - Eric
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
>> For additional commands, e-mail: user-help@struts.apache.org
>>
>>
Re: Field Name Collision?
Posted by Chris Pratt <th...@gmail.com>.
I don't use ModelDriven myself, but as I understand it, it places the Model
Object at the top of the Value Stack, which would make userid be a reference
to an attribute in the Model Object, not in the Action. When you use
user.userid, it's because it's trying to find the user attribute in the
Model Object (on the top of the Value Stack), which fails so it goes a step
down the stack to the Action, where it finds a user attribute to use.
So, it appears Struts is functioning exactly as designed.
(*Chris*)
On Tue, Apr 26, 2011 at 12:55 PM, Dave Newton <da...@gmail.com> wrote:
> Doubt you're doing anything wrong; I'd expect it's how OGNL does its
> lookup but haven't confirmed that.
>
> Dave
>
> On Tue, Apr 26, 2011 at 3:52 PM, Eric Lentz <Er...@sherwin.com>
> wrote:
> > - Struts 2.2.1
> > - Tomcat 6.0
> > - JDK 1.5.0_22
> > - Code example of the problem: http://pastebin.com/eyyJaBg4
> > - Description:
> > I have two fields in my action class: user and userId. The user variable
> > is of type User, which also contains a userId. In both cases userId is of
> > type String.
> >
> > While implementing SessionAware and ModelDriven...
> >
> > Happy path:
> > If I pass a parameter in the URL as follows:
> > http://localhost:8080/Context/test-list.action?user.userId=foo
> >
> > Then user.userId = "foo" when it gets to the action.
> >
> > Not-so-happy path:
> > If I pass a parameter in the URL as follows:
> > http://localhost:8080/Context/test-list.action?userId=foo
> >
> > Then user.userId = "foo" when it gets to the action.
> >
> > Note that in both cases, "foo" was assigned to user.userId, though I used
> > different keys in the URL each time!
> >
> > - Work-around:
> > If I change either one of the names to something that is unique to the
> > other, then it works as one would expect.
> >
> > Am I doing something wrong?
> >
> > - Eric
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
> For additional commands, e-mail: user-help@struts.apache.org
>
>
Re: Field Name Collision?
Posted by Dave Newton <da...@gmail.com>.
Doubt you're doing anything wrong; I'd expect it's how OGNL does its
lookup but haven't confirmed that.
Dave
On Tue, Apr 26, 2011 at 3:52 PM, Eric Lentz <Er...@sherwin.com> wrote:
> - Struts 2.2.1
> - Tomcat 6.0
> - JDK 1.5.0_22
> - Code example of the problem: http://pastebin.com/eyyJaBg4
> - Description:
> I have two fields in my action class: user and userId. The user variable
> is of type User, which also contains a userId. In both cases userId is of
> type String.
>
> While implementing SessionAware and ModelDriven...
>
> Happy path:
> If I pass a parameter in the URL as follows:
> http://localhost:8080/Context/test-list.action?user.userId=foo
>
> Then user.userId = "foo" when it gets to the action.
>
> Not-so-happy path:
> If I pass a parameter in the URL as follows:
> http://localhost:8080/Context/test-list.action?userId=foo
>
> Then user.userId = "foo" when it gets to the action.
>
> Note that in both cases, "foo" was assigned to user.userId, though I used
> different keys in the URL each time!
>
> - Work-around:
> If I change either one of the names to something that is unique to the
> other, then it works as one would expect.
>
> Am I doing something wrong?
>
> - Eric
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