Sorting components using DnD

[tilmanklar]

Hello guys,

I'm working on some web application where I must be able to move components around in order to sort them. I started using an a4j:repeat to build a list of rich:panels and added DnD to it using the standard mechanisms available in the taglib rich. Here's what I got so far:

<rich:panel id="repeatpanel">
 <a4j:repeat rowKeyVar="rowKey" id="repeat" value="#{bb.list}" var="item">
 <rich:panel header="#{item.name}">
 <rich:dropSupport acceptedTypes="Item" dropValue="#{rowKey}"
 reRender="repeat"/>
 <rich:dragSupport dragIndicator=":indicator"
 dragType="Item"
 dragValue="#{rowKey}"
 dragListener="#{bb.processDrop}"/>
 <h:outputText value="Name:" />
 <h:inputText size="50" value="#{item.name}">
 <a4j:support event="onkeyup" reRender="repeatpanel"/>
 </h:inputText>
 </rich:panel>
 <rich:spacer width="100%" height="5"/>
 </a4j:repeat>
 </rich:panel>

After that, I added the following method to the backing bean:

private List<Item> items;

 public void processDrop(DragEvent event) {
 Integer srcIdx = ((Integer)event.getDragValue());
 Integer dstIdx = ((Integer)event.getDropValue());
 Item srcItem = this.items.remove(srcIdx.intValue());
 this.items.add(dstIdx, srcItem);
 System.out.println("processDrop(): moved " + srcIdx + " to " + dstIdx);
 }

When dragging and dropping, the println shows that the dropped rich:panels are moving the items around. So far so good. However, the UI does not render the changes. So I added some more printlns to the methods Item#setName() and Item#getName(). Here's what happens:

getItems(): current order: [ #83 #864 #985 ]
processDrop(): moved 0 to 2
getName() returns: #864
getName() returns: #985
getName() returns: #83
setName("#83")
setName("#864")
setName("#985")
getItems(): current order: [ #83 #864 #985 ]

Just after processDrop, getName() gets called and returns the correct values. But then, setName() overwrites the changes using the old values. How is that possible? Did I take the wrong turn somewhere? Is there a way to find out the source of the setName() calls?

TIA,
Tilman