There is no conversion when passing parameters between components. I'm pretty confident that the fact you are using generics here is irrelevant. When you access the @Parameter for the first time Tapestry calls the getter from the page, and the object returned is the object that you are using in the component.
I've created a small example app with one component that takes both a List<String> and a List<MyMap> (which I extended from TreeMap) and it passes data between the page and component fine. Have you set a breakpoint in the getter method on the page and inspected the map? My guess is that it's corrupt before it's every assigned to the local variable in your component. Josh On Tue, Apr 1, 2008 at 11:42 AM, Alec Leamas <[EMAIL PROTECTED]> wrote: > Thanks for taking time to answer :-) > > I first had all of this working for a single page. *After* that, I > started a refactoring effort to be able to share some parts of the code > with other pages. That is, I'm moving out some working code from the > page (java + template) to a component. All of this seems very straight > forward, besides the fact that the two parameters behaves so > differently. Bottom line: the code runs OK when used in single page, but > there are problems factoring out a component. > > Part of this is the feeling: the parameter passing works in one case > and not in the other. This makes me unhappy. I want to understand > what's possible and not w r to parameter passing, and this seems to be a > little unclear to me. Davor Hrg indicated that there might be some > problems w generics, so I guess this is not that simple(?). And although > I've read what I found about coercion, I wouldn't say I understand this > fully. I *am* that stupid, have to live with it ;-) > > The reasons to extend Map is perhaps outside the scope of this > discussion, although I'm of course ready to go into it this would make > things more clear. > > Maybe this boils down to a simple question before diving into more code: > is Tapestry expected to handle my two parameters of type List<String> > and List<MyMap> in the same way? Or is there s difference between a > List of a "well-known" type and List containing a user defined type? > > --Alec > > > Jonathan Barker wrote: > > > > This is really sounding like something unrelated to Tapestry, and there > > isn't enough code presented to tell. > > > > Do you have proof that your code works outside of Tapestry? Why, and how, > > did you EXTEND TreeMap? Do you have a unit test to prove that your MyMap > > works? > > > > If you can present a non-Tapestry test that works, and corresponding > > Tapestry test that doesn't, then I think you'll find an answer quickly. > > > > Jonathan > > > > > > > > > >> -----Original Message----- > >> From: Alec Leamas [mailto:[EMAIL PROTECTED] > >> Sent: Tuesday, April 01, 2008 8:37 AM > >> To: Tapestry users > >> Subject: Re: T5, newbie: Component parameter passing problems > >> > >> public List<MyMap> getRows() {...} > >> > >> Davor Hrg wrote: > >> > >>> how is getRows declared in your page class ? > >>> > >>> > >>> > >>> > >>> On Tue, Apr 1, 2008 at 2:09 PM, Michael Kolmodin <[EMAIL PROTECTED]> > >>> wrote: > >>> > >>> > >>> > >>>> OK, thanks... > >>>> > >>>> In my page, I have <t:myComponent columns="prop:columns" > >>>> rows="prop:rows"/> > >>>> > >>>> The columns argument, a List<String> is just fine. > >>>> The rows argument, a List<MyMap> is the problem. > >>>> > >>>> The page has a List<MyMap> getRows() which is verified. > >>>> > >>>> Looking in MyComponent.java, I have > >>>> > >>>> @Parameter > >>>> private List<MyMap> rows; > >>>> > >>>> @Parameter > >>>> private List<String> columns; > >>>> > >>>> public String getSomethingStrange() > >>>> { > >>>> return rows.get(0).get( "mail" ); > >>>> } > >>>> > >>>> The latter getter fails. The debug info is from a breakpoint inside > >>>> > >> this > >> > >>>> method. The error I get is a classcast error "java.lang.String cannot > >>>> > >> be > >> > >>>> cast to ...MyMap" If I change the index to 1, there an error "Caused > >>>> by: Index: 1, Size: 1" i. e., index out of bounds. > >>>> > >>>> Davor Hrg wrote: > >>>> > >>>> > >>>>> Tapestry support for Java generics is very limited, > >>>>> you need a value encoder to make this work, > >>>>> > >>>>> also, add more details on who calls what... so more is known > >>>>> of the problem you are trying to solve. > >>>>> > >>>>> > >>>>> Davor Hrg > >>>>> > >>>>> On Tue, Apr 1, 2008 at 1:43 PM, Alec Leamas <[EMAIL PROTECTED]> > >>>>> > >>>>> > >>>> wrote: > >>>> > >>>> > >>>>>> I have problems passing my own datatype(s) to my own component. The > >>>>>> component takes two parameters, one List<String> and one List<MyMap>. > >>>>>> MyMap is declared as MyMap extends TreeMap {...}. > >>>>>> > >>>>>> The first parameter, a list of strings arrives safely to my > >>>>>> > >> component. > >> > >>>>>> However, the other one, seems to be mixed up: when I try to access an > >>>>>> element in my List<MyMap>, it turns out that Tapestry (nothing else > >>>>>> involved) have filled this list with String items, not the expected > >>>>>> MyMap items. In the end, there is a class cast exception when trying > >>>>>> > >> to > >> > >>>>>> access the MyMap items as Maps. > >>>>>> > >>>>>> In the Eclipse debugger, it seems that the value of the List<MyMap> > >>>>>> instance variable is a single string holding what looks like the > >>>>>> serialized value of my List<MyMap> list. The start is > >>>>>> "[{key=value,key=value... > >>>>>> > >>>>>> I've tried to contribute coercions between MyMap<->Map, but this > >>>>>> > >> desn't > >> > >>>>>> seem to help (?). > >>>>>> > >>>>>> Basically, I'm stucked unless I write everything in several big pages > >>>>>> with duplicated code. Don't really want to do that. :-( > >>>>>> > >>>>>> Any hints out there? > >>>>>> > >>>>>> --alec > >>>>>> > >>>>>> PS Version: 5.0.11 DS > >>>>>> > >>>>>> --------------------------------------------------------------------- > >>>>>> To unsubscribe, e-mail: [EMAIL PROTECTED] > >>>>>> For additional commands, e-mail: [EMAIL PROTECTED] > >>>>>> > >>>>>> > >>>>>> > >>>>>> > >>>> -- > >>>> ----------------------------------------------------------------------- > >>>> > >> --- > >> > >>>> Michael Kolmodin Fredsgatan 2 > >>>> Phone: +46 920 269413 S-972 35 Lulea > >>>> Mobile +46 70 551 6507 Sweden > >>>> > >>>> --------------------------------------------------------------------- > >>>> 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] > > -- -- TheDailyTube.com. 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