Follow up: Programmatic ADF Faces Tree holding state across requests

As a further follow up to my recent posts "Back to programming: Programmatic ADF Faces Tree component" and "Follow-up: Programmatic ADF Faces Tree in JDev 11g", this posts shows how to maintain the tree's state across multiple page requests or pages. The basic problem with the previous code was if the page was refreshed, or the tree component existed in different pages, the tree's current state in terms of what has been expanded and collapsed was lost.

To solve this issue, for the tree component in every page where you wish to include and maintain the tree's state, add a binding attribute like follows:

<af:tree var="node" value="#{treeModel.model}" binding="#{treeState.tree}">

In your faces-config.xml file add a new session level bean:

<managed-bean>
  <managed-bean-name>treeState</managed-bean-name>
  <managed-bean-class>TreeState</managed-bean-class>
  <managed-bean-scope>session</managed-bean-scope>
</managed-bean>

And finally define the bean class as:

import oracle.adf.view.faces.component.core.data.CoreTree;
import oracle.adf.view.faces.model.PathSet;

public class TreeState {
   private CoreTree tree;
   private PathSet treePathSet;

   public TreeState() {
   }

   public void setTree(CoreTree tree) {
     treePathSet = tree.getTreeState();
     this.tree = tree;
   }

   public CoreTree getTree() {
     if (treePathSet != null)
     tree.setTreeState(treePathSet);
   }
}

You'll note how the bean across the user's session saves and restores the tree's state each time the web page requests the CoreTree component.

The credit for the seeds of the solution for this post must goto Arjuna Wijeyekoon and his OTN JDev Forum post from 2004. As can be seen the OTN Forums are very valuable for finding solutions.