struts-user  

Re: Handling Date objects in ActionForm gracefully

Mark Lowe
Thu, 25 Mar 2004 15:59:47 -0800

You deal with the conversion else where but not in the form bean, you can argue about it or just believe me. The action form sits between the view and the action, the date conversion goes on between the action and the model.

Your approach isn't that bad its just not to the MVC pattern that struts follows (not that its the only one).

Create a date convertion util class or something.

If you dont want to take my word for it here's what craig had to say albeit in response to a different question

<snippet>
As the original designer of Struts :-), I must point out that the design of
ActionForm (and the recommendation that form bean properties be Strings) is
***very*** deliberate. The reason this is needed is obvious when you consider
the following use case:

* You have an input form that, say, accepts only integers.

* Your form bean property is of type "int".

* The user types "1b3" instead of "123", by accident.

* Based on experience with any garden variety GUI application,
  the user will expect that they receive an error message,
  plus a redisplay of the form ***WITH THE INCORRECT VALUES
  THAT WERE ENTERED DISPLAYED SO THE USER CAN CORRECT THEM***.

* The current Struts environment will throw an exception
  due to the conversion failure.

* The suggested solution will ***hopelessly*** confuse the
  nature of a form bean, which is part of the VIEW tier, with
  model beans that have native data types.

Struts does not include any sort of "user interface component model" where the
details of conversion are hidden inside the user interface component. If that
is what you are after, you should look at a *real* user interface component
model (such as using JavaServer Faces with a Struts application). Corrupting
the functionality of a form bean to *pretend* that it is a user interface
component is only going to create complications for the world.
</snippet>

I hope this helps

Mark

On 25 Mar 2004, at 21:26, Sreenivasa Chadalavada wrote:


Application Tier is strongly typed.

So if the field is a java.util.Date in the database, then the data object will have the method

public DataObject{
        public java.util.Date getAsOfDate()
        public void setAsOfDate(java.util.Date asOfDate) methods.
}

My Action form is:

public MyActionForm extends ActionForm{
        public DataObject getDataObject();
        public void setDataObject(DataObject dataObject);
}

My jsp contains

<html:text property="dataObject.asOfDate"/>

This will fail if the user does not enter any date. I want the (changed) struts framework to handle that.

I did not want to create a new method with type String for every Date field

Hope this explanation helps !!

Thanks and Regards,
 Sree/-


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Mark Lowe <mark.lowe
 @boxstuff.com>

03/25/2004 03:17 PM
Please respond to "Struts Users Mailing List"

       
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        Subject:        Re: Handling Date objects in ActionForm gracefully



Ask yourself why are you trying to convert types for user input?

On 25 Mar 2004, at 21:11, Sreenivasa Chadalavada wrote:

> Do you know if the behavior can be overridden?
>
> Thanks and Regards,
> Sree/-
>
>
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> "Takhar, Sandeep" <Sandeep.Takhar
> @CIBC.ca>
> 03/25/2004 02:53 PM
> Please respond to "Struts Users Mailing List"
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>         To:     "Struts Users Mailing List"  
> <[EMAIL PROTECTED]>
>         cc:
>         Subject:        RE: Handling Date objects in ActionForm  
> gracefully
>
>
> yes it is.  It should be done once per classloader.
>
> When struts populates the dyna form it is string array to string array
> conversion and uses
> populate method of BeanUtils which eventually calls the converters.
>
> sandeep
>
> -----Original Message-----
> From: Sreenivasa Chadalavada [mailto:[EMAIL PROTECTED]
> Sent: Thursday, March 25, 2004 2:47 PM
> To: Struts Users Mailing List
> Subject: Re: Handling Date objects in ActionForm gracefully
>
>
> I am thinking of overriding the struts default mechanism.
> Override the default behavior of  
> org.apache.commons.beanutils.ConvertUtils
>
> by registering
> a valid converter...
>
> I want to know if the above is possible..
>
> Thanks and Regards,
> Sree/-
>
>
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> Mark Lowe <mark.lowe
> @boxstuff.com>
> 03/25/2004 02:36 PM
> Please respond to "Struts Users Mailing List"
>
>
>         To:     "Struts Users Mailing List"
> <[EMAIL PROTECTED]>
>         cc:
>         Subject:        Re: Handling Date objects in ActionForm  
> gracefully
>
>
> Have it as a string and convert it to a date or calendar when you pass
> it back to the model.
>
>
> On 25 Mar 2004, at 20:28, Sreenivasa Chadalavada wrote:
>
>> All,
>>
>> We are facing a problem when we define java.util.Date field in
>> ActionForm.
>>
>> Is there any way to override the default behavior provided by Struts?
>>
>> I very much appreciate your help!!
>>
>> Thanks and Regards,
>> Sree/-
>>
>>
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