You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@myfaces.apache.org by Apache Wiki <wi...@apache.org> on 2007/01/26 02:27:03 UTC
[Myfaces Wiki] Update of "ClearInputComponents" by SimonKitching
Dear Wiki user,
You have subscribed to a wiki page or wiki category on "Myfaces Wiki" for change notification.
The following page has been changed by SimonKitching:
http://wiki.apache.org/myfaces/ClearInputComponents
------------------------------------------------------------------------------
+ === Problem Description ===
+
Sometimes you want to provide a command component (eg a link or button) that performs some server action, and
- renders the same page but with completely "fresh" values for all components. However this doesn't work well
+ renders the same page but with completely "fresh" values for all components.
- when the component is "immediate"; in this case input components get their "submitted value" set during the postback
- and re-render that submitted value even when the backing values for those input components have been reset to default values.
+ When using command components with the normal immediate setting (false), achieving this is just a matter of clearing the beans that the JSF component value attributes access. Any values entered by the user will have been pushed into these beans as part of the Update Model phase, so the components themselves will not be holding any information about submitted data. The action method associated with the command is then run which resets the model, and when the components render themselves they will draw fresh data from the (reset) beans.
+
+ Note that because data is being pushed into the model, the validation phase must run, and therefore any invalid data in the page will cause the action to be skipped, and the page is redisplayed with the validation errors displayed. This is not generally the desired behaviour for a "clear" type operation! The solution is to set attribute immediate=true on the command so that its associated action is invoked before validation is applied to the input components in the same view (see ["How_The_Immediate_Attribute_Works"]).
+
+ However when using command components with immediate=false, things become more complex. All components will retrieve the raw submitted values submitted by the user, but the immediate command will then run before they can be pushed into the backing beans; the components therefore remember this data. When the (immediate) action causes navigation to another view then this is no problem; these components will be discarded anyway. However if the action method causes JSF to go directly to the render phase 'of the same view' [by calling facesContext.renderResponse()], then the components will behave as they do for a validation failure - by displaying the value cached in the component rather than fetching data from the backing bean.
+
- Here are a number of possible solutions
+ Below are a number of possible solutions.
=== Force a new View ===
Call this method from the action method of the immediate command component:
Re: [Myfaces Wiki] Update of "ClearInputComponents" by SimonKitching
Posted by Jeff Bischoff <jb...@klkurz.com>.
Simon,
I noticed a probable mistake in the following line from your addition:
+ However when using command components with immediate=false, things
become more complex.
Here you are actually talking about the scenario immediate=true! You
described immediate=false in a previous paragraph. I have made this
change already for you on the wiki, but if I am mistaken please revert
it. :)
Regards,
Jeff Bischoff
Kenneth L Kurz & Associates, Inc.
Mike Kienenberger wrote:
> Simon,
>
> Since you're working on this page, can you please remove this part at
> the bottom of the page? I've successfully used the "return non-null
> navigation outcome to the same page" in order to reset form values.
>
> Note that this approach has not been tested; if you find it does work,
> then please update this page.
>
> On 1/25/07, Apache Wiki <wi...@apache.org> wrote:
>> Dear Wiki user,
>>
>> You have subscribed to a wiki page or wiki category on "Myfaces Wiki"
>> for change notification.
>>
>> The following page has been changed by SimonKitching:
>> http://wiki.apache.org/myfaces/ClearInputComponents
>>
>> ------------------------------------------------------------------------------
>>
>> + === Problem Description ===
>> +
>> Sometimes you want to provide a command component (eg a link or
>> button) that performs some server action, and
>> - renders the same page but with completely "fresh" values for all
>> components. However this doesn't work well
>> + renders the same page but with completely "fresh" values for all
>> components.
>> - when the component is "immediate"; in this case input components get
>> their "submitted value" set during the postback
>> - and re-render that submitted value even when the backing values for
>> those input components have been reset to default values.
>>
>> + When using command components with the normal immediate setting
>> (false), achieving this is just a matter of clearing the beans that
>> the JSF component value attributes access. Any values entered by the
>> user will have been pushed into these beans as part of the Update
>> Model phase, so the components themselves will not be holding any
>> information about submitted data. The action method associated with
>> the command is then run which resets the model, and when the
>> components render themselves they will draw fresh data from the
>> (reset) beans.
>> +
>> + Note that because data is being pushed into the model, the
>> validation phase must run, and therefore any invalid data in the page
>> will cause the action to be skipped, and the page is redisplayed with
>> the validation errors displayed. This is not generally the desired
>> behaviour for a "clear" type operation! The solution is to set
>> attribute immediate=true on the command so that its associated action
>> is invoked before validation is applied to the input components in the
>> same view (see ["How_The_Immediate_Attribute_Works"]).
>> +
>> + However when using command components with immediate=false, things
>> become more complex. All components will retrieve the raw submitted
>> values submitted by the user, but the immediate command will then run
>> before they can be pushed into the backing beans; the components
>> therefore remember this data. When the (immediate) action causes
>> navigation to another view then this is no problem; these components
>> will be discarded anyway. However if the action method causes JSF to
>> go directly to the render phase 'of the same view' [by calling
>> facesContext.renderResponse()], then the components will behave as
>> they do for a validation failure - by displaying the value cached in
>> the component rather than fetching data from the backing bean.
>> +
>> - Here are a number of possible solutions
>> + Below are a number of possible solutions.
>>
>> === Force a new View ===
>> Call this method from the action method of the immediate command
>> component:
>>
>
>
>
Re: [Myfaces Wiki] Update of "ClearInputComponents" by SimonKitching
Posted by Mike Kienenberger <mk...@gmail.com>.
Simon,
Since you're working on this page, can you please remove this part at
the bottom of the page? I've successfully used the "return non-null
navigation outcome to the same page" in order to reset form values.
Note that this approach has not been tested; if you find it does work,
then please update this page.
On 1/25/07, Apache Wiki <wi...@apache.org> wrote:
> Dear Wiki user,
>
> You have subscribed to a wiki page or wiki category on "Myfaces Wiki" for change notification.
>
> The following page has been changed by SimonKitching:
> http://wiki.apache.org/myfaces/ClearInputComponents
>
> ------------------------------------------------------------------------------
> + === Problem Description ===
> +
> Sometimes you want to provide a command component (eg a link or button) that performs some server action, and
> - renders the same page but with completely "fresh" values for all components. However this doesn't work well
> + renders the same page but with completely "fresh" values for all components.
> - when the component is "immediate"; in this case input components get their "submitted value" set during the postback
> - and re-render that submitted value even when the backing values for those input components have been reset to default values.
>
> + When using command components with the normal immediate setting (false), achieving this is just a matter of clearing the beans that the JSF component value attributes access. Any values entered by the user will have been pushed into these beans as part of the Update Model phase, so the components themselves will not be holding any information about submitted data. The action method associated with the command is then run which resets the model, and when the components render themselves they will draw fresh data from the (reset) beans.
> +
> + Note that because data is being pushed into the model, the validation phase must run, and therefore any invalid data in the page will cause the action to be skipped, and the page is redisplayed with the validation errors displayed. This is not generally the desired behaviour for a "clear" type operation! The solution is to set attribute immediate=true on the command so that its associated action is invoked before validation is applied to the input components in the same view (see ["How_The_Immediate_Attribute_Works"]).
> +
> + However when using command components with immediate=false, things become more complex. All components will retrieve the raw submitted values submitted by the user, but the immediate command will then run before they can be pushed into the backing beans; the components therefore remember this data. When the (immediate) action causes navigation to another view then this is no problem; these components will be discarded anyway. However if the action method causes JSF to go directly to the render phase 'of the same view' [by calling facesContext.renderResponse()], then the components will behave as they do for a validation failure - by displaying the value cached in the component rather than fetching data from the backing bean.
> +
> - Here are a number of possible solutions
> + Below are a number of possible solutions.
>
> === Force a new View ===
> Call this method from the action method of the immediate command component:
>