hi, this is how i do it... one of many possible ways :)
i let tapestry populate a DTO bean that is sent during the validate event through a facade (IOC service) to my businesslayer. there the DTO is then mapped to my BOs. (as in the theory :) because i don't want to write these stupid DTO- BO mappings i have a DTO and a BO interface. the view layer knows only the DTO interface with getter and setter methods. the only thing the facade does is to perform a cast from the DTO interface to the BO interface and to call the BOs validate method. my facade returns a validationResult instance that contains the error messages that are fed into the form component preventing the success event. and sometimes i have to call save() to get a result (username/ password). in this cases i dont use the success event at all (in the login example i return a Link to the welcome page). btw. the facade will catch any exception that might occur during the business transaction. so the view (tapestry) will not know anything about it, except the error messages i set. Another thing you can do is to create a tapestry page that is desgined to display a certain exception. Take a look at the ExcpetionReporter page. IMHO the events provided by tapestry are just fine. most of the time the way the application is designed is the problem. a clean separation of view and businesslayer is crucial. have a look at "Pojos in Action" by Chris Richardson or "Domain Driven Design" by Eric Evans... they are really worth reading. g, kris "Vjeran Marcinko" <[EMAIL PROTECTED]> 08.07.2008 12:03 Bitte antworten an "Tapestry users" <users@tapestry.apache.org> An "Tapestry users" <users@tapestry.apache.org> Kopie Thema Re: [T5] Default ValidationTracker clearing needed? Oh, I didn't know that since I've seen some discussions before that it was "session". Nevertheless, clearing of the input values prior to "success" event still poses slight problem IMO. I am not fond of persisting some entity objects between requests just to be able to see those input values rendered, since this can raise some Hibernate session problems etc... -Vjeran ----- Original Message ----- From: "Kristian Marinkovic" <[EMAIL PROTECTED]> To: "Tapestry users" <users@tapestry.apache.org> Sent: Tuesday, July 08, 2008 11:16 AM Subject: Re: [T5] Default ValidationTracker clearing needed? > hi, > > the Form component was changed some time ago to > use the "flash" persistence strategy for the ValidationTracker > > from the code: > @Persist(PersistenceConstants.FLASH) > private ValidationTracker defaultTracker; > > g, > kris > > > > > "Vjeran Marcinko" <[EMAIL PROTECTED]> > 07.07.2008 21:15 > Bitte antworten an > "Tapestry users" <users@tapestry.apache.org> > > > An > <users@tapestry.apache.org> > Kopie > > Thema > [T5] Default ValidationTracker clearing needed? > > > > > > > > Hi all. > > I posted this as a comment on some closed Jira issue, but nevertheless, I > would like to see comments from everybody... > > ValidationTracker in its current form clears its input values before > "success" event. I guess it is done this way assuming that no error can > happen anymore when "success" is triggered, and one doesn't want to see > those values even if staying on same page. > > Two frequent cases come to my mind when this simply doesn't hold water... > > 1. Cases when SOME validation is performed inside business methods, thrown > > as checked exceptions when not satisfied. This validation cannot be > performed prior to calling business method. I don't believe that in those > cases I should place calling the business method inside unnatural > onValidate > handler. I believe it should still be placed inside onSuccess, since all a > > priori validation has passed well. > > Example is typical call on UserDao from within EditPage.onSuccess() method > : > > UserDao.save(User user) throws UsernameReservedException > > I still have to be able to catch this exception and somehow dispay error > with all input values still shown. > > 2. Frequently, when using search forms, I display search results on same > page where form resides. Being able to show all search form criteria > values > is great stuff, since user can see what criteria he just entered. Since > this > is normal type of request flow, input values should ont be cleared before > "success". > > > MY SUGGESTION: > > ValidationTracker should be persisted wtih "flash" strategy, and values > should never be cleared. If one stays on same page, regardless if there > was > an error (in any handler method - onValidate, onSuccess...) or not, input > > values would still be there. If user decides to leave the page, "flash" > strategy will ensure that these values will not be visible he comes back > to > this page later. > In rare cases when user wants to stay on the same page, but doesn't want > to > see input values, he can explicitly clear those values. > > Thoughts? > > -Vjeran > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.138 / Virus Database: 270.4.6/1539 - Release Date: 7.7.2008 > 18:35 > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
