Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/viewers/UpdatableTreeContentProvider.java
if (newTreeViewer != treeViewer) {
            if (treeViewer != null) {
                treeViewer.removeTreeListener(expandListener);
            }
            
            this.treeViewer = newTreeViewer;
            if (newTreeViewer != null) {
                newTreeViewer.addTreeListener(expandListener);
            }
        }
    }
    public IReadableSet getKnownElements() {
        return elements;
    }
    private Collection computeKnownElements() {
        return Collections.unmodifiableCollection(mapElementToValueTreeNode.keySet());
    }
    public boolean isDirty(Object element) {
        ValueTreeNode node = (ValueTreeNode) mapElementToValueTreeNode.get(element);
        if (node == null) {
            return false;
        }
        return node.isDirty();
    }
    
    public TreeViewer getViewer() {
        return treeViewer;
    }
}