Hi Andy, I do not agree, it's not just a documentation problem I've opened a bug for the specific Dialog problem:
https://issues.apache.org/jira/browse/TAPESTRY-1699 I think default use just doesn't behave the way you expect it to behave (that is a bug, even though a minor one). But I think there's also a generic enhancement to parameters that could be made that I describe in https://issues.apache.org/jira/browse/TAPESTRY-1700 I think this could provide a new interesting feature and many misunderstanding like the one me and Andrea (I guess) had. If you think it's useful I could provide some code On 8/9/07, andyhot <[EMAIL PROTECTED]> wrote: > Well, it looks like the hidden parameter is an in-out one, > and it's probably that way by design I guess. The 'value' and 'index' > parameters of @For > work similarly but that's more straightforward after reading the docs. > > Anyway, I think we should just document this. > > Martino Piccinato wrote: > > Finally I think we were both wrong and that I opened two useless tickets: > > > > in fact, as stated in the documentation default-value attribute now > > accept any kind of binding and actually CREATES the binding if no > > other binding is present. > > > > In your case: > > > > org.apache.tapestry.binding.AbstractBinding.createReadOnlyBindingException( > > AbstractBinding.java:115)) when I call into my rewindFormComponent method > > this code: > > > > setStartRow(sliderValue); > > > > and I set into jwc file: > > <parameter name="startRow" required="no" cache="true" > > default-value="ognl:0"/> > > > > means that at some point, during rewind, some of your code/components > > is calling a "setStartRow" to update the binding but the binding is > > invariant (ognl:0 is a costant!) so it's a read only binding (you > > can't "change the value" of a constant) so the > > ReadOnlyBindingException is correctly throwned. > > > > What you should do (if you really need to change the bound value) is > > bind to a containing component method (e.g. value="ognl:currentRow") > > that will contain the logic of when to return the default value and > > when not to. > > > > It's also possible NOT TO BIND the parameter by default, initializing > > the parameter method after the component finishLoad() phase, in your > > case it would be: > > > > In jwc: > > <parameter name="startRow"/> > > > > In component: > > > > public void finishLoad() { > > super.finishLoad(); > > setStartRow(0); > > } > > > > > > The fact is that default-value with invariant values (literal, > > ognl:<constant>, ecc.) make sense just if it's a read only binding, At > > the same time default-value with ognl expressions referring to > > containing component methods would break component encapsulation > > making assumptions on the exact method signature the containing > > component should implement (also its optional/default status would be > > questionable...). > > > > As for my specific Dialog component problem I think there's still a > > bug because the component IS actually trying to "write" the invariant > > default-value binding in hide/show methods so after 2 invalid ticket I > > hope I'm goig to open a valid one now. > > > > > > > > On 7/30/07, Martino Piccinato <[EMAIL PROTECTED]> wrote: > > > >> Posted one for the parameter issue > >> > >> https://issues.apache.org/jira/browse/TAPESTRY-1682 > >> > >> and another one for the Dialog component: > >> > >> https://issues.apache.org/jira/browse/TAPESTRY-1683 > >> > >> I didn't do it first because I was trying to investigate myself but I > >> really have no time to do this now. > >> > >> Ciao > >> > >> Martino > >> > >> On 7/30/07, Andrea Chiumenti <[EMAIL PROTECTED]> wrote: > >> > >>> Well, I try to investigate into this, meanwhile if you could be so kind to > >>> post a jira... > >>> > >>> ciao, > >>> kiuma > >>> > >>> On 7/30/07, Martino Piccinato <[EMAIL PROTECTED]> wrote: > >>> > >>>> Well, I'm having a very similar behaviour with Dialog component that > >>>> by default has a true parameter for optional parameter "hidden". > >>>> > >>>> <parameter name="hidden" default-value="true" /> > >>>> > >>>> It seems that if you set a constant value ("ognl:0" or "true") to a > >>>> parameter then the parameter itself is regarded as "Invariant" by > >>>> AbstractBinding that will refuse you to use any setter on it (it does > >>>> not have a reference to a method but to a... constant) and throw the > >>>> exception. > >>>> I don't have the exception if I just "override" the constant default > >>>> value with an ognl reference to a couple of setters/getters method > >>>> (returning the default value in case the property is not initialized). > >>>> > >>>> In my opinion this is a bug with "parameter" but I haven't been able > >>>> to investigate more and I'm quite surprised nobody stepped into this > >>>> problem before, see my neglected Dialog mails of some days ago :-) > >>>> > >>>> > >>>> > >>>> On 7/30/07, Andrea Chiumenti <[EMAIL PROTECTED]> wrote: > >>>> > >>>>> this is the stack trace > >>>>> > >>>>> > >>>>> > >>>> org.apache.tapestry.binding.AbstractBinding.createReadOnlyBindingException > >>>> ( > >>>> > >>>>> AbstractBinding.java:115) > >>>>> org.apache.tapestry.binding.ExpressionBinding.setObject( > >>>>> ExpressionBinding.java:196) > >>>>> $EditTable_16.setStartRow($EditTable_16.java) > >>>>> org.jfly.web.components.edittable.EditTable.rewindFormComponent( > >>>>> EditTable.java:541) > >>>>> > >>>>> On 7/30/07, Andrea Chiumenti <[EMAIL PROTECTED]> wrote: > >>>>> > >>>>>> Hello! > >>>>>> I'm having this exception ( > >>>>>> > >>>>>> > >>>> org.apache.tapestry.binding.AbstractBinding.createReadOnlyBindingException > >>>> > >>>>>> (AbstractBinding.java:115)) when I call into my rewindFormComponent > >>>>>> > >>>> method > >>>> > >>>>>> this code: > >>>>>> > >>>>>> setStartRow(sliderValue); > >>>>>> > >>>>>> and I set into jwc file: > >>>>>> <parameter name="startRow" required="no" cache="true" > >>>>>> default-value="ognl:0"/> > >>>>>> > >>>>>> > >>>>>> Who can help me please ? > >>>>>> > >>>>>> Thx, kiuma > >>>>>> > >>>>>> > >>>> --------------------------------------------------------------------- > >>>> To unsubscribe, e-mail: [EMAIL PROTECTED] > >>>> For additional commands, e-mail: [EMAIL PROTECTED] > >>>> > >>>> > >>>> > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
