I must have misunderstood how this works, no luck yet...
I created a squeezer for java.util.Vector that handles a collection of Item
(id, name) objects, and preserves the id property of the Item object. The
name properties should then be populated from request parameters (text
fields). The name properties are not populated with this approach. They are
however populated if I always initialize the items collection in
pageBeginRender().
The Vector-squeezer works, the page property items has the correct objects
with the correct ids set after rewind is complete, but not the name values
that I entered before submit...
I just don't get it... Maybe it's time to call it a day and celebrate the
weekend :)
Inge
On 2/17/06, Inge Solvoll <[EMAIL PROTECTED]> wrote:
>
> Yes, that's correct, when I use this approach, the collection displays the
> correct content in the form listener. But:
>
> When I do this, the collection is serialized, causing a long Base64
> encoded string. I don't want that, becaus it may cause my html to become
> very large and too big to submit.
>
> I might be able to solve this by creating my own datasqueezer for
> collections.
>
> Anyway, thanks a lot, I see now why my collections are never
> auto-populated!
>
> Inge
>
> On 2/17/06, Todd O'Bryan <[EMAIL PROTECTED]> wrote:
> >
> > As long as your collection is Serializable, you don't need a custom
> > DataSqueezer. The problem is that Tapestry isn't saving the
> > information about the collection itself. This is the problem I was
> > having with my String[].
> >
> > Add a hidden field above your @For to save the items info:
> >
> > <input type="hidden" jwcid="@Hidden" value="ognl:items" /> <!-- I
> > don't think "ognl:" is necessary in 4.0, but I'm still using 3-->
> >
> > and getItems() will not return null in the listener.
> >
> > Todd
> >
> >
> > On Feb 17, 2006, at 4:52 AM, Inge Solvoll wrote:
> >
> > > Does there exist an example (vlib or similar) of a page that only gets
> >
> > > information from database on render, and that uses a custom
> > > datasqueezer and
> > > no db fetching for the rewind phase? My ideal design is that all known
> > > information in the rewind phase comes from request parameters, that
> > > way many
> > > synchronization issues can be avoided (request not matching content
> > > from
> > > database or other state).
> > >
> > > Inge
> > >
> > > On 2/16/06, Inge Solvoll < [EMAIL PROTECTED]> wrote:
> > >>
> > >> Yes, items is always null in pageBeginRender. If I remove the else
> > >> clause,
> > >> it is also null in the form listener. The else clause just
> > >> prevents null
> > >> values before render.
> > >>
> > >> I actually expect the values to be null in pageBeginRender, but I
> > >> expect
> > >> the collection to be populated in the end of the rewind, in the form
> > >> listener...
> > >>
> > >> Inge
> > >>
> > >> On 2/16/06, Ryan <[EMAIL PROTECTED]> wrote:
> > >>>
> > >>> It appears your problem is that getItems() will always be null in
> > >>> pageBeginRender because at that point parameters have not been
> > >>> bound.
> > >>> Try removing that else clause.
> > >>>
> > >>> Ryan
> > >>>
> > >>> On 2/16/06, Inge Solvoll < [EMAIL PROTECTED]> wrote:
> > >>>> I guess my (first) problem is simpler than this discussion, I'll
> > >>>> try
> > >>> to
> > >>>> explain:
> > >>>>
> > >>>> When I submit my form, I expect my page properties to be updated
> > >>> during
> > >>>> rewind automatically, without me having to write any java code
> > >>>> to make
> > >>> that
> > >>>> happen. But so far I haven't understood how this happens. I include
> > >>> here a
> > >>>> simple code example that I think illustrates my problem quite well.
> > >>> Why is
> > >>>> my collection always empty when the form listener is reached? If
> > >>>> I run
> > >>> the
> > >>>> initItems() method on both rewind and render, the values from the
> > >>> request
> > >>>> parameters are written into the page properties.
> > >>>>
> > >>>> My ultimate question is: Do I really have to get the items list
> > >>>> from
> > >>> the
> > >>>> database during rewind? Isn't there a way to avoid this, making
> > >>> tapestry
> > >>>> automatically build the items collection from the request
> > >>>> parameters?
> > >>> As I
> > >>>> wrote in another similar post on the list about DataSqueezer, I've
> > >>> tried
> > >>>> creating a datasqueezer for this, but the collection is still
> > >>>> showing
> > >>> up
> > >>>> empty.
> > >>>>
> > >>>> My HTML file:
> > >>>>
> > >>>>
> > >>> --------------------------------------------------------------------
> >
> > >>> ------
> > >>>>
> > >>>> <body jwcid="@Body">
> > >>>>
> > >>>> <form jwcid="@Form" listener="listener:formListener">
> > >>>>
> > >>>> <span jwcid="@For" source="ognl:items"
> > >>>> value="ognl:currentItem">
> > >>>> <span jwcid="@Insert" value="ognl: currentItem.name"/><br>
> > >>>> <input type="text" jwcid="@TextField" value="ognl:
> > >>> currentItem.name"/>
> > >>>> <br>
> > >>>> </span>
> > >>>>
> > >>>> <input type="button" jwcid="@Submit" value="Submit form now"/>
> > >>>>
> > >>>> </form>
> > >>>> </body>
> > >>>>
> > >>>> -------------------------------------------------------------
> > >>>>
> > >>>> <page-specification class="Test">
> > >>>> <property name="items"/>
> > >>>> <property name="currentItem"/>
> > >>>> </page-specification>
> > >>>>
> > >>>> -------------------------------------------------------------
> > >>>>
> > >>>>
> > >>>> public abstract class Test extends BasePage implements
> > >>>> PageBeginRenderListener {
> > >>>>
> > >>>> static Log log = LogFactory.getLog(Test.class);
> > >>>>
> > >>>> public abstract Collection getItems();
> > >>>> public abstract void setItems(Collection c);
> > >>>>
> > >>>> public void pageBeginRender(PageEvent event) {
> > >>>>
> > >>>> if (!getRequestCycle().isRewinding()) {
> > >>>> initItems();
> > >>>> }
> > >>>> else {
> > >>>> if (getItems() == null) {
> > >>>> setItems(new Vector());
> > >>>> }
> > >>>> }
> > >>>> }
> > >>>>
> > >>>> public void formListener(IRequestCycle cycle) {
> > >>>> Collection items = getItems();
> > >>>> for (Iterator iter = items.iterator(); iter.hasNext();) {
> > >>>> Item currItem = (Item) iter.next();
> > >>>> log.debug("Current item id: " + currItem.getId() + ",
> > >>>> name: " +
> > >>>> currItem.getName());
> > >>>> }
> > >>>> }
> > >>>>
> > >>>> private void initItems() {
> > >>>> Collection items = new Vector();
> > >>>>
> > >>>> items.add(new Item(new Long(1), "Item 1"));
> > >>>> items.add(new Item(new Long(2), "Item 2"));
> > >>>>
> > >>>> setItems(items);
> > >>>> }
> > >>>> }
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>> On 2/15/06, Ryan <[EMAIL PROTECTED]> wrote:
> > >>>>>
> > >>>>> You may want to look at the method prepareForRender(). This is the
> >
> > >>>>> method that handles binding of properties to form values. It is
> > >>>>> also
> > >>>>> called just before the component is rendered and in the order in
> > >>> which
> > >>>>> they are rendered on the page (where pageBeginRender is called
> > >>> before
> > >>>>> anything renders and is called in an undefined order). Also note
> > >>> that
> > >>>>> prepareForRender is not called if the component is not rendered
> > >>>>> (for
> > >>>>> instance if it is in an @Conditional that evaluates to false).
> > >>>>>
> > >>>>> I have received the best results from using pageBeginRender for
> > >>>>> initializing page properties that are static (ie known at all
> > >>>>> times
> > >>>>> during render, for instance a property select model property) and
> > >>>>> using prepareForRender in other times.
> > >>>>>
> > >>>>> Ryan
> > >>>>>
> > >>>>> On 2/14/06, Inge Solvoll < [EMAIL PROTECTED]> wrote:
> > >>>>>> I would like to provoke some debate on whether this is a good
> > >>> design
> > >>>>> pattern
> > >>>>>> or not:
> > >>>>>>
> > >>>>>> public void pageBeginRender(PageEvent event) {
> > >>>>>> initState();
> > >>>>>> readItemsFromDatabase();
> > >>>>>> }
> > >>>>>>
> > >>>>>> private Collection readItemsFromDatabase() {
> > >>>>>> return getDatabaseConnection().getItems();
> > >>>>>> }
> > >>>>>>
> > >>>>>> private void initState() {
> > >>>>>> // Init all crucial page state here
> > >>>>>> }
> > >>>>>>
> > >>>>>> My problem is that some ids in hidden inputs are needed by the
> > >>> initState
> > >>>>>> method. These values are not available in the pageBeginRender
> > >>> method
> > >>>>> during
> > >>>>>> rewind, because the Hidden components containing them haven't
> > >>>>>> been
> > >>>>> rendered
> > >>>>>> yet. I need this state information on a per-request basis, not
> > >>>>> per-session,
> > >>>>>> so it is not possible to persist the page property. So far, I'm
> > >>> solving
> > >>>>> this
> > >>>>>> by using good-old request parameters, and reading them the old
> > >>> servlet
> > >>>>> way
> > >>>>>> in the pageBeginRender method like this:
> > >>>>>>
> > >>>>>> String crucialId = getRequest().getParameter("crucialId");
> > >>>>>> page.setCrucialId(new Long(crucialId));
> > >>>>>>
> > >>>>>> I generally run into a lot of problems trying to find a good
> > >>> pattern for
> > >>>>>> setting up data to fit with the RequestCycle. I have ended up
> > >>> doing the
> > >>>>>> database reading in the pageBeginRender method, meaning that my
> > >>> data for
> > >>>>> the
> > >>>>>> page is being read on every single rewind and render. I find it a
> >
> > >>> bit
> > >>>>> hard
> > >>>>>> to understand how to achieve this:
> > >>>>>>
> > >>>>>> On render:
> > >>>>>> - Read data from database and set page properties
> > >>>>>>
> > >>>>>> On rewind:
> > >>>>>> - Create non-null, empty, page properties ready to be populated
> > >>> from the
> > >>>>>> request.
> > >>>>>>
> > >>>>>> My rewind step here often fails, and I don't see why. My page
> > >>> properties
> > >>>>>> don't seem to be populated, when I leave them as, say, a non-null
> >
> > >>> empty
> > >>>>>> java.util.Collection to be populated with items from the request.
> > >>>>>>
> > >>>>>> Long and not very concentrated post, I actually don't know where
> > >>> to
> > >>>>> start
> > >>>>>> here :)
> > >>>>>>
> > >>>>>> Inge
> > >>>>>>
> > >>>>>>
> > >>>>>
> > >>>>>
> > >>> --------------------------------------------------------------------
> > >>> -
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> > >>>>> [EMAIL PROTECTED]
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> > >>> [EMAIL PROTECTED]
> > >>>>>
> > >>>>>
> > >>>>
> > >>>>
> > >>>
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> > >>>
> > >>>
> > >>
> >
> >
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> >
> >
>
