Here's an app that does what I believe is trying to be done:
// Page
public class News {
@Property
private Integer _newsId;
public void onActivate(Integer newsId) {
_newsId = newsId;
}
public Integer onPassivate() {
return _newsId;
}
}
// Page Template
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";>
<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd";>
<body>
<t:newsQuote newsId="newsId" />
</body>
</html>
// Component
public class NewsQuote {
@Parameter
private Integer _newsId;
@Inject
private ComponentResources _resources;
void beginRender(MarkupWriter writer) {
writer.element("ul");
for (int i = 0; i < 5; ++i) {
writer.element("li");
Link link = _resources.createActionLink("show", false,
i);
writer.element("a", "href", link.toURI());
writer.write("News number " + i);
writer.end();
if (_newsId != null && _newsId.equals(i)) {
writer.write(" You picked " + _newsId);
}
writer.end();
}
writer.end();
}
// The Action handler
void onShow(Integer id) {
// stored into the bound parameter, feeding it back into the
page
_newsId = id;
}
}
The url http://localhost:8080/news/4
Renders
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd";>
<html xmlns="http://www.w3.org/1999/xhtml";>
<head>
<link href="/assets/tapestry/default.css" rel="stylesheet" type="text/css">
</head>
<body>
<ul>
<li><a href="/news.newsquote:show/0?t:ac=4">News number 0</a></li>
<li><a href="/news.newsquote:show/1?t:ac=4">News number 1</a></li>
<li><a href="/news.newsquote:show/2?t:ac=4">News number 2</a></li>
<li><a href="/news.newsquote:show/3?t:ac=4">News number 3</a></li>
<li><a href="/news.newsquote:show/4?t:ac=4">News number 4</a> You picked 4</li>
</ul>
</body>
</html>
Josh
On Wed, Apr 30, 2008 at 2:49 PM, Chris Lewis <[EMAIL PROTECTED]> wrote:
> I do hope we've missed a simpler way, but I don't think it's surfaced
> yet. Regarding parameters, how would that address the issue? NewsQuote
> displays a collection of items as links that represent selectable items
> (expressed as links). The action must be taken based on the user's
> selection, so a component parameter doesn't apply here.
> The event-based approach seems a theoretical perfect fit, but I can't
> see how to do it without using @Persist (which Janos wants to avoid).
> The only other thing I thought of is to have the NewsQuote component
> generate pagelinks based on the containing page instead of action links.
> This circumvents entirely the need for the events as the value will be
> in the page context, does not not make 2 requests, and ultimately gets
> the job done. It doesn't seem as elegant to me, but does the job and is
> completely decoupled from the page.
>
> Still not sure if we've had our epiphany yet :-)
>
> chris
>
>
> Josh Canfield wrote:
> >> I mean really, how is that any simpler than
> >> dealing directly with query parameters?
> >>
> >
> > Hehe... I have to admit that I was solving a much more complicated
> > problem than the original question, probably brought on by an earlier
> > request about dynamic component rendering... I was shooting for
> > completely decoupled context handling for an unknown assortment of
> > components. Say you have 50 potential portlet components on a page
> > that may get included multiple times and may or may not add to the
> > context of the page, you probably don't want to manage that through
> > individual page properties.
> >
> > Anyway,
> > Isn't the straight forward solution to this problem to use component
> > parameters as Joel pointed out? If your NewsQuote component accepts a
> > newsId parameter, that binding is bi-directional. When the event
> > occurs in the component it calls the setter of the bound parameter,
> > which updates the value in the page and gets put back into the url via
> > context returned by onPassivate. When the value is set during render
> > time the component grabs the news item and renders it, if not it grabs
> > the top five and displays them...
> >
> > Perhaps as Joel pointed out we're just making this too complicated and
> > we should be the ones kicked out!
> >
> > Josh
> >
> > On Wed, Apr 30, 2008 at 1:27 PM, Chris Lewis <[EMAIL PROTECTED]> wrote:
> >
> >> I see how this whole push on/pull off environment will solve the issue,
> >> but it just seems so nasty. I mean really, how is that any simpler than
> >> dealing directly with query parameters? I point at this only to
> >> highlight that perhaps Janos has brought to light a legitimately rough
> >> edge in T5, or else there's a cleaner way to do it and we're all just
> >> missing it. I'm convinced that the event system is the way to go as it
> >> seems a natural fit, but the redirect-after-action part is rendering it
> >> useless without using @Persist! Let me share what I've put together, and
> >> maybe someone will find the missing piece. I have a working test and
> >> I'll abbreviate the code here and assume a few things:
> >>
> >> (coming in another message - i tripped the spam filter :-| )
> >>
> >>
> >> Josh Canfield wrote:
> >>
> >>> Are you trying to keep the news id out of the url? Doesn't sound like
> >>> it from your response to not doing the redirect. Since that's the
> >>> case, why not add it to the page context?
> >>>
> >>> I suppose if you were building a portal with several components then
> >>> keeping track of component parameters could get unwieldy. If you were
> >>> showing a news article from the news portlet, and a stock highlight
> >>> from the stock portlet... At that point you're sort of building a
> >>> framework on a framework.
> >>>
> >>> You could build your page such that it accumulated context from it's
> >>> components. Push a ComponentContext object into the Environment
> >>> onActivate, and setupRender in your page (env gets cleared before
> >>> render phase, not sure if there is a better way than doing it in
> >>> both.) Then collect component parameter mappings. onPassivate for your
> >>> page would organize and return these as it's context (you might want
> >>> to sort them to get consistent results)
> >>>
> >>> Your url might look like this:
> >>>
> >>> http://localhost/context/mypage/cc/news/4527/stock/MCD
> >>>
> >>> Then onactivate you init the ComponentContext from the url keying off
> >>> the "cc" to grab the remaining parameters and use them as key/value
> >>> for the components. The your components do something like:
> >>>
> >>> @Environmental
> >>> private ComponentContext _compContext;
> >>>
> >>> void setupRender() {
> >>> Long newsId = _compContext.getLong(_resources.getId());
> >>> }
> >>>
> >>> void onPickNewsItem(Long id) {
> >>> _compContext.put(_resources.getId(), id);
> >>> }
> >>>
> >>>
> >>> Josh
> >>>
> >>> On Wed, Apr 30, 2008 at 5:23 AM, János Jarecsni
> >>> <[EMAIL PROTECTED]> wrote:
> >>>
> >>>
> >>>> Hi Chris,
> >>>>
> >>>> I try to explain :)
> >>>> Say, you have a "NewsQuote" component, which shows a few lines from the 5
> >>>> latest news. At the and of each quotations, there a "More" link. Now,
> >>>> when
> >>>> the user clicks on this link (an action link, for that matter), the
> >>>> NewsQuote component will set a request scope info saying that the news
> >>>> with
> >>>> ID=4527 is requested. And when it comes to the "News" component (it is
> >>>> able
> >>>> to show the text of a given news in full), it simply looks at this piece
> >>>> of
> >>>> info, and loads the news with id 4527 (or gets it from an app level cache
> >>>> :)) and renders it.
> >>>>
> >>>> Hope it tells something about what I am up to :)
> >>>>
> >>>> thx
> >>>> Janos
> >>>>
> >>>> 2008/4/30 Chris Lewis <[EMAIL PROTECTED]>:
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>> Honestly it's difficult for me to imagine a situation where I'd do that
> >>>>> because it seems to violate a degree of encapsulation that tapestry
> >>>>> imposes as a "freeing law" of the framework. The epicenter of that being
> >>>>> that one should not think in terms of low-level idioms such as request
> >>>>> parameters, and instead replace those with a higher level of application
> >>>>> logic that eclipses them entirely (when possible). That's not to say
> >>>>> that your perspective is flawed, but from the small bit of understanding
> >>>>> I've taken from your posts I can't see why one would do what you want.
> >>>>> The thing that I've been saying is missing here is, what are you trying
> >>>>> to do? I don't mean technically, I mean what is the end result for the
> >>>>> user? Understanding this is critical, but even if I don't your problem
> >>>>> can still be solved by using a session to serve as an arbitrary holder.
> >>>>> If you've settled on this architecture, why not write such a generic
> >>>>> service and move on?
> >>>>>
> >>>>>
> >>>>>
>
> --
> http://thegodcode.net
>
>
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