Sure, that's clear to me now but isn't there the potential for a side
effect.
Consider case 1 where the programmer looks at the docs and sees that String
is the default and creates a TextField without setting the type. Then there
is case 2 where the programmer sets the type to String anyway just so there
is no confusion. Potentially these two cases behave differently.
Now consider case 1 again but there is a maintenance change which requires a
different model being used which in turn results in the 'default' no longer
being derived. Yet again a different behaviour.
On Mon, Mar 31, 2008 at 3:01 PM, Johan Compagner <[EMAIL PROTECTED]>
wrote:
> We already try to guess the type if the user doesn't set it (but not in
> constructor but much later when the component/model hierarchy is
> completed)
> But if the type is a String.class we will not set it and ignore it.
>
> So you shouldn't set the type to String.class by default, only set it when
> you really want a String to String conversion.
>
> johan
>
>
> On Mon, Mar 31, 2008 at 3:46 PM, Eric Rotick <[EMAIL PROTECTED]> wrote:
>
> > I guess, if this was a real issue then more users would have reported
> it.
> > However, as a TextField is such an innocent component then any confusing
> > behaviour should be addressed. Maintaining a common behaviour of
> > setConvertEmptyInputStringToNull would do that and your proposed
> solution
> > looks good.
> >
> > One thing which was confusing from the javadocs level is the implication
> > that the setting of a type is defaulted; i.e.
> >
> > public TextField( String id, Class type ) {
> > super( id );
> > setType( type );
> > ...
> > }
> >
> > public TextField( String id ) {
> > super( id );
> > Class type = workOutTypeFromModelIfPossible( );
> > if( type == null ) {
> > type = String.class;
> > }
> > setType( type );
> > ...
> > }
> >
> > In other words, there is always a type set unless the model is one which
> > does not allow for it to be derived in which case String is assumed as
> in
> > the FormComponent javadocs for setType.
> >
> > Eric.
> >
> > On Mon, Mar 31, 2008 at 1:37 PM, Johan Compagner <[EMAIL PROTECTED]>
> > wrote:
> >
> > > Ok i guess if if quickly look at the code.
> > > If you dont do your own converter then it defaults i guess to the
> > > DefaultConverter
> > > that does this:
> > >
> > > public Object convertToObject(String value, Locale locale)
> > > {
> > > if (value == null)
> > > {
> > > return null;
> > > }
> > > if ("".equals(value))
> > > {
> > > if (((Class)type.get()) == String.class)
> > > {
> > > return "";
> > > }
> > > return null;
> > > }
> > >
> > > So if it is a String class and the input is "" it does return ""
> > >
> > > we could change this:
> > >
> > > final IConverter converter = getConverter(getType());
> > > try
> > > {
> > > convertedInput = converter.convertToObject(getInput(),
> > > getLocale());
> > > }
> > >
> > > in FormComponent..
> > > If it is of Type String then after the conversion we still check for
> the
> > > convert empty to null and do that..
> > >
> > > Because now that boolean is of no use if you are setting the Type
> > >
> > > johan
> > >
> > > johan
> > >
> > >
> > > On Mon, Mar 31, 2008 at 2:34 PM, Johan Compagner <[EMAIL PROTECTED]
> >
> > > wrote:
> > >
> > > > if you are setting the type The converter is called and not
> > > > convertValue()
> > > > i am still not really happy with this but for 1.3/1.4 this is the
> way
> > it
> > > > works
> > > >
> > > > And i guess the String converter that does String to String doesnt
> óok
> > > at
> > > > that convert empty input to null value at all
> > > >
> > > > Do you have your own?
> > > >
> > > > johan
> > > >
> > > >
> > > >
> > > > On Mon, Mar 31, 2008 at 1:38 PM, Eric Rotick <[EMAIL PROTECTED]>
> > > wrote:
> > > >
> > > > > I do have the type set and I've been reading WICKET-606 and I'm
> > using
> > > > > 1.3.2and there is no converter and convertInput is not called.
> > > > >
> > > > > I've now written some code to show that there is a difference.
> > > > >
> > > > > form.add( new TextField( "text1", new PropertyModel( this, "text1"
> )
> > )
> > > > > );
> > > > > form.add( new TextField( "text2", new PropertyModel( this, "text2"
> )
> > > > > ).setConvertEmptyInputStringToNull( true ) );
> > > > > form.add( new TextField( "text3", new PropertyModel( this, "text3"
> )
> > > > > ).setConvertEmptyInputStringToNull( false ) );
> > > > > form.add( new TextField( "text4", new PropertyModel( this, "text4"
> > ),
> > > > > String.class ) );
> > > > > form.add( new TextField( "text5", new PropertyModel( this, "text5"
> > ),
> > > > > String.class ).setConvertEmptyInputStringToNull( true ) );
> > > > > form.add( new TextField( "text6", new PropertyModel( this, "text6"
> > ),
> > > > > String.class ).setConvertEmptyInputStringToNull( false ) );
> > > > >
> > > > > produces this
> > > > >
> > > > > Setting text1 to [null]
> > > > > Setting text2 to [null]
> > > > > Setting text3 to []
> > > > > Setting text4 to []
> > > > > Setting text5 to []
> > > > > Setting text6 to []
> > > > >
> > > > > So,
> > > > >
> > > > > - text1 and text2 are the same because
> > > > > setConvertEmptyInputStringToNull is true by default
> > > > > - text3 does what would be expected
> > > > > - text4 I'm not sure about
> > > > > - text5 and text6 are anomalous as either one or the other
> should
> > > > > produce a null
> > > > >
> > > > > I guess the main problem is that I'm not sure what is supposed to
> > > > > happen. I
> > > > > though that having set the type to String meant that the normal
> > string
> > > > > processing took place and setConvertEmptyInputStringToNull did the
> > > job.
> > > > >
> > > > > As it is, I've learned more about how things work and I can
> overcome
> > > my
> > > > > problem. However, if anyone wants me to continue with this I would
> > be
> > > > > happy
> > > > > to do so.
> > > > >
> > > > > Eric.
> > > > >
> > > > > On Fri, Mar 28, 2008 at 8:58 PM, Johan Compagner <
> > [EMAIL PROTECTED]
> > > >
> > > > > wrote:
> > > > >
> > > > > > Are you sure you dont have the type set?
> > > > > > Is a converter used or is convertInput called?
> > > > > >
> > > > > > On 3/28/08, Eric Rotick <[EMAIL PROTECTED]> wrote:
> > > > > > > Hmm, it's not working for me.
> > > > > > >
> > > > > > > There's one other thing I spotted. The docs say that a
> TextField
> > > > > > defaults to
> > > > > > > String.class even if it cannot work out the class from the
> > model.
> > > My
> > > > > > model
> > > > > > > is not one that allows for reflection to determine the class
> and
> > > > > > initially
> > > > > > > all input to the TextField was being set as null even when
> there
> > > was
> > > > > > some.
> > > > > > > As soon as I added the parameter to set the class to String it
> > > > > started
> > > > > > > saving strings correctly.
> > > > > > >
> > > > > > > I will have a look at the code to see if there's anything
> > obvious.
> > > > > > >
> > > > > > > Eric.
> > > > > > >
> > > > > > > On Fri, Mar 28, 2008 at 4:37 PM, Igor Vaynberg <
> > > > > [EMAIL PROTECTED]>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > TexField.setConvertEmptyInputStringToNull( true ) worked
> fine
> > > for
> > > > > me
> > > > > > > > in a quickstart...
> > > > > > > >
> > > > > > > > -igor
> > > > > > > >
> > > > > > > >
> > > > > > > > On Fri, Mar 28, 2008 at 8:25 AM, Eric Rotick <
> > > [EMAIL PROTECTED]
> > > > > >
> > > > > > wrote:
> > > > > > > > > I've just been reading the section on Forms and validation
> > in
> > > > > Wicket
> > > > > > in
> > > > > > > > > Action and have tried
> > > > > > > > >
> > > > > > > > > AbstractValidator av = new AbstractValidator( ) {
> > > > > > > > > protected void onValidate( IValidatable
> validatable
> > )
> > > {
> > > > > > > > > // No nothing
> > > > > > > > > }
> > > > > > > > > public boolean validateOnNullValue( ) {
> > > > > > > > > return true;
> > > > > > > > > }
> > > > > > > > > };
> > > > > > > > >
> > > > > > > > > adding one of these to the TextField but still an empty
> > > string
> > > > > gets
> > > > > > > > > returned.
> > > > > > > > >
> > > > > > > > > All I want to do is get a null string rather than an
> empty
> > > > > string
> > > > > > from
> > > > > > > > a
> > > > > > > > > TextField. Has nobody had this use case?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On Thu, Mar 27, 2008 at 5:02 PM, Eric Rotick <
> > > > > [EMAIL PROTECTED]>
> > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > I've just realised that the database is getting filled
> > with
> > > > > > columns
> > > > > > > > of
> > > > > > > > > > empty strings which then don't cause the 'not null'
> test
> > to
> > > > > trip.
> > > > > > > > > >
> > > > > > > > > > The culprit is the TextField returning an empty string
> > > rather
> > > > > > than a
> > > > > > > > null.
> > > > > > > > > > I can see there are some special considerations for
> > > returning
> > > > > a
> > > > > > null
> > > > > > > > and I
> > > > > > > > > > want to understand how they will effect me. However,
> I've
> > > > > tried
> > > > > > > > > >
> > > > > > > > > > TexField.setConvertEmptyInputStringToNull( true )
> > > > > > > > > >
> > > > > > > > > > with no effect and using
> > > > > > > > > >
> > > > > > > > > > new TextField( id ) {
> > > > > > > > > > public boolean isInputNullable() {
> > > > > > > > > > regturn true;
> > > > > > > > > > }
> > > > > > > > > > };
> > > > > > > > > >
> > > > > > > > > > also with no effect.
> > > > > > > > > >
> > > > > > > > > > I'm assuming I'm not the first person to see this
> effect
> > > and
> > > > > I
> > > > > > guess
> > > > > > > > it's
> > > > > > > > > > lack of understanding rather than some implicit
> behaviour
> > > but
> > > > > I
> > > > > > can't
> > > > > > > > find
> > > > > > > > > > anything guiding on the subject.
> > > > > > > > > >
> > > > > > > > > > In this case, the string has no special formatting, it
> > just
> > > > > needs
> > > > > > to
> > > > > > > > be
> > > > > > > > > > stored verbatim in the database but the application
> logic
> > > in
> > > > > the
> > > > > > > > backend
> > > > > > > > > > uses an empty string in a different way than a null
> > string
> > > > > and,
> > > > > > yes,
> > > > > > > > maybe
> > > > > > > > > > the database should also have a column check but it
> > doesn't
> > > > > at
> > > > > > > > present.
> > > > > > > > > >
> > > > > > > > > > Any pointers?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > >
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