Bug 157174 [Viewers] Refactor new Viewer API
We are yet not completely happy with the API and refactor it.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
}
	public boolean isExpandable(Object element) {
		if (getContentProvider() instanceof ILazyTreeContentProvider) {
			TreeItem treeItem = (TreeItem) internalExpand(element, false);
			if (treeItem == null) {
				return false;
			}
			virtualMaterializeItem(treeItem);
			return treeItem.getItemCount() > 0;
		}
		return super.isExpandable(element);
	}
	protected Object getParentElement(Object element) {
		if (!(element instanceof TreePath)
				&& (getContentProvider() instanceof ILazyTreeContentProvider)) {
			ILazyTreeContentProvider lazyTreeContentProvider = (ILazyTreeContentProvider) getContentProvider();
			return lazyTreeContentProvider.getParent(element);
		}
		return super.getParentElement(element);
	}
	protected void createChildren(Widget widget) {
		if (getContentProvider() instanceof ILazyTreeContentProvider) {
			final Item[] tis = getChildren(widget);
			if (tis != null && tis.length > 0) {
				
				for (int i = 0; i < tis.length; i++) {
					tis[i].getText();
				}
				return;
			}