[SOLVED] Tree cannot be used dynamically

[tonico]

The UI component org.primefaces.component.tree.Tree lacks a valueExpression based setter for the "selection" attribute. This prevents to map the selection of a node to a managed bean. Here is an example

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org.primefaces.component.tree.Tree uiPrimeTree = new org.primefaces.component.tree.Tree();
uiPrimeTree.setId("mytree123");
uiPrimeTree.setWidgetVar("mytree123");
uiPrimeTree.setSelectionMode("single");
uiPrimeTree.setSelection( <<<<  OBJECT >>>> );  // here is the ISSUE. It is expected an object here, but there is no "setSelectionValueExpression". 
uiPrimeTree.setVar("node");
...

For the above, pointing to an mbean TreeNode property through ...

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setValueExpression("selection","#{myBean.mySelectionTreeNode}")

... would not work, because it would be resolved on the spot at component creation time and the component would not be able to set the selected node back ( it would lose its reference (. What we really need is a sort of "setSelectionValueExpression" where the value expression is alive and kept to resolve the setter and getter of that property.

With the above, what happens is the following exception:

SEVERE: java.lang.NullPointerException
at org.primefaces.component.tree.Tree.processUpdates(Tree.java:318)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1242)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1242)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1242)
at org.primefaces.component.tabview.TabView.processUpdates(TabView.java:257)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1242)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1242)
at org.primefaces.component.tabview.TabView.processUpdates(TabView.java:257)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1242)
at javax.faces.component.UIForm.processUpdates(UIForm.java:281)

[cagatay.civici]

I think you need to create a proper value expression using ExpressionFactory then set it.

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setValueExpression("selection", selectionVE);

[tonico]

Thanks ! I totally missed to realize that method. Works great.