<div width="100%" apply="test.TestComposer">
	 <custom-attributes org.zkoss.zul.grid.rod="false"/>
	<grid id="grid"/>
	<button id="button" label="Run"/>
</div>

public class TestComposer extends GenericForwardComposer {
	private Grid grid;

	private Button button;

	private RowRenderer rowRenderer;

	private MyModel model;

	private class MyModel extends GroupsModelArray {

		public MyModel(String[] data, Comparator<String> comp) {
			super(data, comp);
		}

		public void update(int group) {			
			fireEvent(GroupsDataEvent.GROUPS_CHANGED, 0, group, group);
		}

		@Override
		protected Object createGroupHead(Object[] groupdata, int index, int col) {
			return "HEAD";
		}

		@Override
		protected Object createGroupFoot(Object[] groupdata, int index, int col) {
			return "FOOT";
		}
	}

	private class MyRowRenderer implements RowRenderer {

		@Override
		public void render(Row row, Object data) throws Exception {
			new Label((String) data).setParent(row);
		}

	}

	@Override
	public void doAfterCompose(final Component component) throws Exception {
		super.doAfterCompose(component);

		String[] data = new String[4];
		data[0] = "test0";
		data[1] = "test0";
		data[2] = "test1";
		data[3] = "test1";

		rowRenderer = new MyRowRenderer();
		grid.setRowRenderer(rowRenderer);

		model = new MyModel(data, new Comparator<String>() {
			@Override
			public int compare(String o1, String o2) {
				return o1.compareTo(o2);
			}
		});
		grid.setModel(model);

		button.addEventListener(Events.ON_CLICK, new EventListener() {
			@Override
			public void onEvent(Event arg0) throws Exception {
				model.update(0);
			}
		});
	}

}