I don't think that would be consistently unique beyond the objects life.
On 1/27/06, Schulte Marcus <[EMAIL PROTECTED]> wrote: > > Hm, interesting problem. Now, your objects are equal but they are not the > same. So, I guess, you could use a keyExpression parameter referring to > the > objects' hashcode. In standard vm's, Object.hashCode() returns different > values for different instances. > > so, I'd try: > > <div jwcid="@For" source="ognl:rsvpList" value="ognl:currentRsvp" > keyExpression="hashCode"> > > would that workf for you? > > Marcus > > > -----Original Message----- > > From: Chris Conrad [mailto:[EMAIL PROTECTED] > > Sent: Thursday, January 26, 2006 9:49 PM > > To: Tapestry users > > Subject: Re: Non-intuitive behavior from the For component > > > > > > I think the problem here (and this is also in regards to using the > > keyProvider parameter and equals method) is I'm dealing with a list > > of objects which are 100% legitimately equal to each other. And > > that's really what I want. I want the For component to take a list > > of equal objects to render the page and then, during the rewind, > > update that list of objects according to their index in the list. > > When I start I have no identifying information about the list of > > objects, all I know is that I need x number of them. > > > > To try and explain in a different way ... if you look at the Form > > section of the Quick Start guide you can see the standard > > pattern for > > having a user fill in a form to create a new object. In the Quick > > Start guide it's creating a new ProjectRelease. So, as in the > > example, in your pageBeginRender you instantiate a blank > > ProjectRelease and when the form is submitted, the fields of the > > ProjectRelease are updated according to the values in the form. I > > want to do the same thing but instead of creating a single > > ProjectRelease, I want to create a list of ProjectReleases. > > > > Does that help any? > > > > --Chris > > > > On Jan 26, 2006, at 12:36 PM, Jesse Kuhnert wrote: > > > > > Hmmm....But that only causes more confusion I'm afraid :( > > > > > > Ohhhhhh....I think what you are doing sort of sounds right, > > but you > > > still > > > can't expect the For component to be able to know the difference > > > between all > > > of your objects if the equals() method on them doesn't > > enforce some > > > sort of > > > uniqueness. > > > > > > Have you tried playing with the "match" parameter to For? I've > > > normally used > > > the "ListEdit" component for things like this in the past. Would > > > love to > > > hear if "match" or some of the other parameters solve your problem. > > > > > > On 1/26/06, Chris Conrad <[EMAIL PROTECTED]> wrote: > > >> > > >> Sorry to reply twice, but I thought some code snippets might make > > >> things clearer. Here is what I do in my pageBeginRender: > > >> > > >> rsvpList = new ArrayList<Rsvp>(numberAttending); > > >> > > >> for (int i = 0; i < numberAttending; i++) { > > >> Rsvp rsvp = new Rsvp(); > > >> rsvp.setId(i); > > >> rsvp.setAttending(true); > > >> > > >> rsvpList.add(i, rsvp); > > >> } > > >> > > >> setRsvpList(rsvpList); > > >> > > >> My listener method looks like: > > >> > > >> // Reset the ids to 0 > > >> List<Rsvp> rsvpList = getRsvpList(); > > >> for (Rsvp rsvp : rsvpList) { > > >> rsvp.setId(0); > > >> } > > >> > > >> getRsvpData().setRsvpList(rsvpList); > > >> > > >> And then in my HTML template I use it like this: > > >> > > >> <div jwcid="@For" source="ognl:rsvpList" > > >> value="ognl:currentRsvp"> > > >> <div jwcid="@Any" element="div" > > >> class="ognl:evenOdd.next"> > > >> <p class="floatLeft"> > > >> <label jwcid="@FieldLabel" > > >> field="component:guestName">Guest's Name</label> > > >> <input jwcid="guestName" size="30"/> > > >> </p> > > >> > > >> <p class="floatLeft"> > > >> <label jwcid="@FieldLabel" > > >> field="component:meal">Meal</label> > > >> <input jwcid="meal"/> > > >> </p> > > >> <br class="clear"/> > > >> </div> > > >> > > >> The bit that bothers me is that in my pageBeginRender I > > need to do > > >> this: > > >> rsvp.setId(i); > > >> > > >> and in my listener I need to do this: > > >> > > >> // Reset the ids to 0 > > >> List<Rsvp> rsvpList = getRsvpList(); > > >> for (Rsvp rsvp : rsvpList) { > > >> rsvp.setId(0); > > >> } > > >> > > >> I need to do that exclusively so that the For component can update > > >> the List correctly. > > >> > > >> Hopefully that makes things a little clearer. > > >> > > >> --Chris > > >> > > >> On Jan 26, 2006, at 11:58 AM, Jesse Kuhnert wrote: > > >> > > >>> Hmmm. . > > >>> > > >>> I do these sort of things a lot, esp. with hibernate. I've found > > >>> the For > > >>> component to incredibly useful, but maybe the identification of > > >>> objects part > > >>> could be made more clear? > > >>> > > >>> I think the PropertySelectionModel problem could be solved if you > > >>> used the > > >>> "BeanPropertySelectionModel" class found in > > >>> http://tacos.sourceforge.netinstead. It makes turning a list of > > >>> hibernate objects into the selection > > >>> model a one-line argument. > > >>> > > >>> Let me know if you try that and still find problems. > > >>> > > >>> On 1/26/06, Chris Conrad <[EMAIL PROTECTED]> wrote: > > >>>> > > >>>> Hello everyone, > > >>>> > > >>>> I'm working a tiny little RSVP for a friend. While doing so I > > >>>> found, > > >>>> what seems to me at least, a very non-intuitive result > > from the For > > >>>> component. Basically the behavior I want is: > > >>>> > > >>>> 1. The user navigates to the RSVP page and is provided a > > drop down > > >>>> box to select the number of people who will be attending > > the event. > > >>>> > > >>>> 2. The user is given a list of text entry boxes (to enter the > > >>>> name of > > >>>> the guest) and drop downs (to select the meal the guest wants). > > >>>> > > >>>> 1 was simple to accomplish though having to create a > > >>>> PropertySelectionModel is kinda a pain for something this simple. > > >>>> Where things got hairy is 2. Basically the code flow is: in the > > >>>> listener for the form submit in #1, I grab the number of guests > > >>>> attending and set that on the meal selection page. The meal > > >>>> selection page's pageBeginRender creates a List of x RSVP objects > > >>>> where x is the number of guests attending. Then the > > meal selection > > >>>> page uses a For component to loop through the List of RSVP > > >>>> objects so > > >>>> that, in the first pass everything is blank and then > > when the guest > > >>>> submits, those RSVP objects in the List get filled in with the > > >>>> details the guest entered. > > >>>> > > >>>> Now, what actually happened is the first RSVP object in > > the list is > > >>>> continually updated over and the others are never touched. When > > >>>> tracing through the For components code, it appears to > > be trying to > > >>>> match the serialized object saved in the form against the ones > > >>>> in the > > >>>> List to "intelligently" pick which one to update. But > > since all of > > >>>> the RSVP objects were the same to start with, and the > > For component > > >>>> doesn't update it's internal mapping after updating an object, it > > >>>> just ignored everything in the list after the first item. Or, I > > >>>> guess more accurately, it continually matched the first > > item in the > > >>>> List and so it just repeatedly updated that one RSVP object. To > > >>>> work > > >>>> around this, I needed to set the RSVP's id in the > > >>>> pageBeginRender to > > >>>> a different value for each RSVP object and then reset them back > > >>>> to 0 > > >>>> just before sending them to Hibernate to persist (if I > > don't reset > > >>>> them to 0, Hibernate things it's a detached object and ends up > > >>>> updating a row instead of adding a new row). > > >>>> > > >>>> This work around seems very much like a hack to me. Is > > there a way > > >>>> to make the For component do the right thing (i.e. > > actually iterate > > >>>> over the array when rewinding instead of assuming it knows what > > >>>> it's > > >>>> doing)? I did try playing with the match parameter and that > > >>>> completely breaks everything, none of the objects in the List get > > >>>> updated. It seems that my use case isn't so terribly strange > > >>>> that it > > >>>> would be this difficult to accomplish in Tapestry. > > >>>> > > >>>> Thanks, > > >>>> --Chris > > >>>> > > >>>> > > ------------------------------------------------------------------- > > >>>> -- > > >>>> To unsubscribe, e-mail: tapestry-user- > > >>>> [EMAIL PROTECTED] > > >>>> For additional commands, e-mail: tapestry-user- > > >>>> [EMAIL PROTECTED] > > >>>> > > >>>> > > >> > > >> > > >> > > --------------------------------------------------------------------- > > >> To unsubscribe, e-mail: > > [EMAIL PROTECTED] > > >> For additional commands, e-mail: tapestry-user- > > >> [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] > >
