PartialFor
Extension of Tapestry's For component which allows for more efficient looping over lists of elements during ajax request/responses. The parameters provided by For are left out of this spec, for those values/meanings see the referenced tapestry page.
This component will not render the contents of a particular loop during an ajax request if the key value of the element/component doesn't exist as an updateComponent to the original request. The values will still be iterated over, just not rendered.
Parameters
| Name | Type | Direction | Required | Default | Description |
|---|---|---|---|---|---|
| keyProvider | IKeyProvider | in | no | IdentityKeyProvider | Converter from elements to keys. Used by tree to identify node ids. |
| partialBlock | PartialRenderBlock | in | no | Provides ability to have callbacks performed on a component during partial renders in case component requires maintaing some sort of internal state even if each item specified in the source isn't actually rendered. | |
| evenOdd | org.apache.tapestry.bean.EvenOdd | in | no | The evenodd bean that should be incremented for each loop iteration, mainly used to maintain state on non-rendered items. |
Body: rendered
Informal parameters: allowed
Reserved parameters:
Examples
Using the refresh/effects demo page
HTML template
<div id="countries">
<span jwcid="foreachItem" >
<div jwcid="@Any" class="ognl:beans.evenOdd.next" id="ognl:currItem.toString()" >
<div>
<a jwcid="linkToggle" class="toggle">
<span jwcid="@Insert" value="ognl:currSelected ? 'Hide' : 'Details'"/>
</a>
<span jwcid="@Insert" value="ognl:currItem.displayCountry"
class="ognl:currSelected ? 'detailHeading' : 'heading'"/>
</div>
<span jwcid="@If" condition="ognl:currSelected">
<div class="countryDetail">
<div class="flag">
<img jwcid="flagImage" width="34" height="18"/><br/>
<span jwcid="@Insert" value="ognl:currItem.country"/>
</div>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
In consequat lectus a eros. Vestibulum tortor. Cras sapien.
Morbi sed ipsum. Class aptent taciti sociosqu ad litora
torquent per conubia nostra, per inceptos hymenaeos. Fusce
aliquam auctor tortor.</p>
<p style="color: #666">Rendered on: <span jwcid="insertTime"/>.</p>
</div>
</span>
</div>
</span>
</div>
Page specification
<component id="foreachItem" type="tacos:PartialFor">
<binding name="source" value="items"/>
<binding name="value" value="currItem"/>
<binding name="evenOdd" value="ognl:page.beans.evenOdd" />
</component>
Java sources
public abstract class PartialPrototype extends BasePage {
public static final DateFormat DATE_FORMAT =
DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.LONG);
public List getItems() {
Set countries = new HashSet();
Locale[] locales = Locale.getAvailableLocales();
List items = new ArrayList(locales.length);
for (int i = 0; i < locales.length; i++) {
Locale l = locales[i];
if (!"".equals(l.getDisplayCountry())
&& !countries.contains(l.getCountry())) {
items.add(l);
countries.add(l.getCountry());
}
}
Collections.sort(items, new Comparator() {
public int compare(Object o1, Object o2) {
Locale l1 = (Locale) o1;
Locale l2 = (Locale) o2;
return l1.getDisplayCountry().compareTo(l2.getCountry());
}
});
return items;
}
public void toggleItem(IRequestCycle cycle) {
String item = (String) cycle.getListenerParameters()[0];
Set s = getSelectedItems();
if (s.contains(item)) {
s.remove(item);
} else {
s.add(item);
}
setSelectedItems(s);
AjaxWebRequest ajax =
(AjaxWebRequest)cycle.getAttribute(AjaxWebRequest.AJAX_REQUEST);
if (ajax != null) ajax.addStatusResponse("File selected..");
}
public boolean isCurrSelected() {
return getSelectedItems().contains(getCurrItem().toString());
}
public abstract Locale getCurrItem();
public abstract Set getSelectedItems();
public abstract void setSelectedItems(Set selectedItems);
}