TreeStore DragNrop activity not reflected in TreeStore

Question

I created a simple DragNDrop editor to modify a tree to be persisted in my db. (Using GXT 2.2.5 can't upgrade)

I have a TreePanel constructed with a TreeStore. The TreePanel is both a TreePanelDragSource and TreePanelDropTarget.

The drag/drop works fine; As a test, I used the TreeStore from an existing, open Dialog window. As I drag/drop in the editor, the other window immediately shows the tree changes.

However, when I fetch the TreeStore to save it, the nodes are not rearranged in the Store. How do I get the reorganized tree structure?

TIA

Answer 1

My solution

Apparently there is no way to directly get at the Tree structure altered by Drag and Drop.
I reasoned that TreePanelView = TreePanel.getView() might have the Drag and Drop chaanges.
By examining TreePanelView in the debugger after a drag and drop I devise this solution:
/*
* These 'My' classes are used to access the internal tree within TreePanelView.
* The internal tree reflects Drag and Drop activity,
* which is NOT reflected in the TreeStore.
*/
private class MyTreePanel<M extends ModelData> extends TreePanel<M> {
    public MyTreePanel(TreeStore<M> ts) {
        super(ts);
        view = new MyView<M>();
        view.bind(this, store);
    }
    public MyView<M> getMyView() {
        return (MyView<M>) getView();
    }
}
private class MyView<M extends ModelData> extends TreePanelView<M> {
    public MyTreeStore<M> getTreeStore() {
        return (MyTreeStore<M>) this.treeStore;
    }
}
private class MyTreeStore<M extends ModelData> extends TreeStore<M> {
    public MyTreeStore() {
        super();
    }
    public Map<M, TreeModel> getModelMap() {
        return modelMap;
    }
}
To extract the tree altered by Drag and Drop:
MyTreePanel<ModelData> myTree; //Initialize the TreeStore appropriately

// After Drag and Drop activity, get the altered tree thusly:
Map<ModelData, TreeModel> viewMap = myTree.getMyView().getTreeStore().getModelMap();

The TreeModel in viewMap is actually a BaseTreeModel.
The ModelData are the objects I originally loaded into TreeStore.
I had to:
1 - Iterate over viewMap, extract "id" from BaseTreeModel and create a reverse map,
    indexed by "id" and containing my ModelData objects.
2 - Fetch root BaseTreeModel node from viewMap using root ModelData of original tree.
3 - Walk the BaseTreeModel tree.
    At each node, fetched ModelData objects by "id" from the reverse map.

In this way I reconstructed the tree altered by Drag and Drop.