I think I'm on the right track, but I still need a little guidance.
I'm getting problems when trying to render my component. I'm getting
an org.apache.tapestry.BindingException with the message:
Value for parameter 'model' in component BreadCrumbPage/nav.chooser is
null, and a non-null value is required.
The parameter 'model' is the model for the PropertySelection component
within my BreadCrumb component.
To use the BreadCrumbs component, I define it like this in my .page file:
<property-specification name="source"
persistent="yes"
type="org.jk.tapestryutils.components.breadcrumbs.IBreadCrumbSource"/>
<component id="nav" type="taputil:BreadCrumbs">
<binding name="source" expression="source"/>
<binding name="homeTitle" expression="'Home'"/>
<binding name="delimiter" expression="' > '"/>
</component>
IBreadCrumbSource defines one method, which is loadChildrenOf( int i).
The BreadCrumbs component uses this to populate the dropdown. So I
tried doing a lazy initialization in the prepareForRender method:
if (getModel() == null)
{
setModel(new
ValueStringPropertySelectionModel(getSource().loadChildrenOf(0)));
}
but the 'source' object is null. How do I tell my component to use
the source object that is defined in the .page file?
I don't know if this is needed but I'll post it anyway:
BreadCrumbs.jwc:
<component-specification allow-body="no"
allow-informal-parameters="no"
class="org.jk.tapestryutils.components.breadcrumbs.BreadCrumbs">
<parameter name="homeTitle"
direction="in"
required="yes"
type="java.lang.String"/>
<parameter name="source"
direction="in"
required="yes"
type="org.jk.tapestryutils.components.breadcrumbs.IBreadCrumbSource"/>
<parameter name="delimiter"
required="yes"
direction="in"
type="java.lang.String"/>
<property-specification name="values"
persistent="yes"
type="java.util.List"/>
<property-specification name="selected"
persistent="yes"
type="org.jk.tapestryutils.form.IValueString"/>
<property-specification name="model"
persistent="yes"
type="org.jk.tapestryutils.form.ValueStringPropertySelectionModel" />
<property-specification name="currentValue"
type="org.jk.tapestryutils.form.IValueString"/>
<component id="homeLink" type="DirectLink">
<binding name="listener" expression="navHome"/>
</component>
<component id="homeTitle" type="Insert">
<binding name="value" expression="homeTitle"/>
</component>
<component id="ancestorLink" type="LinkSubmit">
<binding name="listener" expression="navLink"/>
<binding name="selected" expression="selected"/>
<binding name="tag" expression="currentValue"/>
</component>
<component id="ancestors" type="Foreach">
<binding name="source" expression="values"/>
<binding name="value" expression="currentValue"/>
</component>
<component id="ancestor" type="Insert">
<binding name="value" expression="currentValue.name"/>
</component>
<component id="delimit" type="Insert">
<binding name="value" expression="delimiter"/>
</component>
<component id="chooser" type="PropertySelection">
<binding name="value" expression="selected"/>
<binding name="model" expression="model"/>
</component>
<component id="goButton" type="Submit">
<binding name="value" expression="'Go'"/>
<binding name="listener" expression="navGo"/>
</component>
</component-specification>
Thanks,
Jer
On 7/27/05, Robert Zeigler <[EMAIL PROTECTED]> wrote:
> You do it exactly like in a page.
> Extend BaseComponent, specify the extended class as your component class
> in the .jwc file. Define your listeners methods in your component class.
> In your component, anywhere you're adding listeners, just do
> ognl:listeners.<listenername>
> And that's it. Your page never has to worry about there being listeners
> in the component.
>
> Robert
>
> Jer Kah wrote:
> > Hello,
> >
> > I have a simple component that combines several existing components
> > (DirectLinks, a select box and submit button) into one component.
> > I've created an html template and a jwc for it so far, but I think I
> > have to subclass BaseComponent. The problem I'm having is that
> > whenever I use this component in a page, I have write listener methods
> > for the directLinks (all the directlinks use the same listener) and
> > for the submit button. I don't want to write these listeners in every
> > page that uses this component.
> >
> > Can I define these listeners in a subclass of BaseComponent? If so,
> > does someone have a simple example of how to do this? Right now, I
> > have to bind the listeners for the component in the page file, but
> > these methods will always do the same thing and I don't want to define
> > them in every .page file.
> >
> >
> > Thanks,
> > Jer
> >
> > ---no need to read further if you're not interested, but it may give
> > you some more insight ----
> >
> >
> > This component is a breadcrumb navigation component. Our data is very
> > hierarchical, (each row in the db has a 'ParentID' field), so there's
> > a select box at the end of the breadcrumbs so that you can select the
> > next child to go to.
> >
> > It starts off showing one link ( a 'Home' link) , a select box and
> > submit button labelled "Go". The select box shows all data in the db
> > at the top of the hierarchy. When you select an option and then hit
> > the "Go" button, another link will be placed next to the Home link and
> > before the select box.
> >
> > Home |________| V | |GO|
> >
> > // pick an option, click "Go" and then it changes to:
> >
> > Home > chosenOption |________| V | |GO|
> >
> > As long as there are children to the last option chosen, they will be
> > populated in the select box. Each of our pages has an associated ID
> > to go along with it (the value of the last chosen option, or 0 if none
> > have been chosen yet).
> >
> > If you click a breadcrumb, the pages' ID will update and all the
> > breadcrumbs after the clicked breadcrumb will go away.
> >
> > As you can see, the listener methods for the links and 'go' button are
> > very well defined and won't be changing. I hate having to copy and
> > paste the listener methods into each page that wants to use this
> > componnent and I know there must be a better way to do it than this
> > way. It seems like the component should know how to do this by
> > itself.
> >
> > If you have any ideas or suggestions, please let me know. I'm new to
> > making components and I don't know the best way forward.
> >
> > Thanks,
> > Jer
> >
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