Cast error trying to access tree binding

Question

JDeveloper version 11.1.2.1.0
java.util.ArrayList cannot be cast to oracle.jbo.uicli.binding.JUCtrlHierBinding
Hi All
I'm using code from ADF Code Corner (http://www.oracle.com/technetwork/developer-tools/adf/learnmore/78-man-expanding-trees-treetables-354775.pdf) to try and programmatically set the tree node disclosure level when the page is initially rendered. The tree's DisclosedRowKeys property is set to #{viewScope.FieldPickerHandler.newDisclosedTreeKeys}. The code for the handler method that's causing the problem is below. First you can see that I have commented out Frank's original code on lines 5, 6 & 8 because for some reason this did not find the tree component (always returned null). So instead I have set the tree component's Binding property to #{viewScope.FieldPickerHandler.jsfTree} to make the component instance available in the handler and this seems to work. However when the code hits line 16 I get the class cast exception at the head of this post.
One significant variation from the Code Corner example is that my tree is based on a POJO model that is populated programmatically from a VO (as posted by Lucas Jellema http://technology.amis.nl/blog/2116/much-faster-adf-faces-tree-using-a-pojo-as-cache-based-on-read-only-view-object-showing-proper-leaf-nodes-again) hence my root node set, and each node's child set, is declared as "List<FieldPickerNode> nodes = new ArrayList<FieldPickerNode>();".
Does the way the POJO tree is constructed make it incompatible with the Code Corner node expansion approach? Can anyone suggest how I can modify my handler bean code to work with the POJO tree?
Thanks
Adrian
PS The tree's Value property is set to #{viewScope.FieldPickerHandler.treemodel} where treemodel is a managed property of the bean - I guess this mean my tree is not ADF-bound?
1 public RowKeySetImpl getNewDisclosedTreeKeys() {
2 if (newDisclosedTreeKeys == null) {
3 newDisclosedTreeKeys = new RowKeySetImpl();
4
5// FacesContext fctx = FacesContext.getCurrentInstance();
6// UIViewRoot root = fctx.getViewRoot();
7 //lookup thetree component by its component ID
8// RichTree tree = (RichTree)root.findComponent("t1");
9 //if tree is found ....
10 if (jsfTree != null) {
11 //get the collection model to access the ADF binding layer for
12 //the tree binding used. Note that for this sample the bindings
13 //used by the tree is different from the binding used for the tree
14 //table
15 CollectionModel model = (CollectionModel)jsfTree.getValue();
16 JUCtrlHierBinding treeBinding = (JUCtrlHierBinding)model.getWrappedData();
Edited by: blackadr on 03-Nov-2011 17:56

Answer 1

Hello Frank et al
Still struggling valiantly to create a POJO tree that uses the ADF binding layer. Rather than referencing the treemodel directly from the component I have now added a method to my model class that returns the set of root nodes as an ArrayList:
public List<FieldPickerNode> getRootNodes() {
if (treemodel == null) {
treemodel = initializeTreeModel();
return rootNodes;
and my FieldPickerNode class also now has a method to return its children as an ArrayList. The model class is managed in view scope. So I drag the rootNodes collection from the Data Controls panel into my panel collection and get the option to create it as an ADF tree. Great. I add the method to get the children as an accessor and the bindings end up looking like this:
<iterator Binds="root" RangeSize="25" DataControl="FieldPickerModel" id="FieldPickerModelIterator"/>
<accessorIterator MasterBinding="FieldPickerModelIterator" Binds="rootNodes" RangeSize="25"
DataControl="FieldPickerModel" BeanClass="view.picker.FieldPickerNode" id="rootNodesIterator"/>
<tree IterBinding="rootNodesIterator" id="rootNodes">
<nodeDefinition DefName="view.picker.FieldPickerNode" Name="rootNodes0">
<AttrNames>
<Item Value="nodeID"/>
</AttrNames>
<Accessors>
<Item Value="children"/>
</Accessors>
</nodeDefinition>
</tree>
The tree component looks like this:
<af:tree value="#{bindings.rootNodes.treeModel}" var="node"
selectionListener="#{bindings.rootNodes.treeModel.makeCurrent}"
rowSelection="single" id="t1">
<f:facet name="nodeStamp">
<af:outputText value="#{node}" id="ot1"/>
</f:facet>
</af:tree>
To my untrained eye this all seems to look ok but when I run the page I get two null pointer errors in the browser and a couple thousand lines of repeated stack in the log viewer. In the early stages of the log there's a message "<BeanHandler> <getStructure> Failed to build StructureDefinition for : view.picker.FieldPickerModel" which I feel can't be good but is in the depths of the framework so difficult for me to debug (am in the process of requesting the ADF source). I've shown the message below with a few lines of context either side.
Can you think of any other lines of enquiry I can follow to progress this? For example are there other attributes or methods that I need to add to my tree model classes in order to support the ADF binding?
For background, the reason I started pursuing the POJO tree in the first place was because for large hierarchies the VO driven tree is unacceptably slow given that it fires SQL for each individual node disclosure. Linking the tree model directly to the component demonstrates just how quick the POJO approach is but I would like to have it go through the ADF bindings so I have more scope to customise the tree behaviour.
Any pointers or help you (or anyone) can give would be very much appreciated.
Adrian
<ADFLogger> <end> Refreshing binding container
<DCExecutableBinding> <refreshIfNeeded> [40] DCExecutableBinding.refreshIfNeeded(338) Invoke refresh for :rootNodesIterator
<DCIteratorBinding> <refresh> [41] DCIteratorBinding.refresh(4438) Executing and syncing on IteratorBinding.refresh from :rootNodesIterator
<ADFLogger> <begin> Instantiate Data Control
<BeanHandler> <getStructure> Failed to build StructureDefinition for : view.picker.FieldPickerModel
<MOMParserMDS> <parse> [42] MOMParserMDS.parse(226) No XML file /view/picker/picker.xml for metaobject view.picker.picker
<MOMParserMDS> <parse> [43] MOMParserMDS.parse(228) MDS error (MetadataNotFoundException): MDS-00013: no metadata found for metadata object "/view/picker/picker.xml"
<DefinitionManager> <loadParent> [44] DefinitionManager.loadParent(1508) Cannot Load parent Package : view.picker.picker
<DefinitionManager> <loadParent> [45] DefinitionManager.loadParent(1509) Business Object Browsing may be unavailable