dynamic grid and sorting

myColumn.setSort("auto")

package test;

public class Item implements Comparable {
	private int _value;
	private String _data;

	public Item(int value, String data) {
		super();
		this._value = value;
		this._data = data;
	}

	public int getValue() {
		return this._value;
	}

	public String getData() {
		return this._data;
	}
	
	public int compareTo(Object obj) throws ClassCastException {
		if (!(obj instanceof Item))
			throw new ClassCastException("Error msg here.");
		Item Itemobj = (Item) obj;
		return this._data.compareTo(Itemobj.getData());
	}
}

<zk>
<window apply="ctrl.Composer">
	<grid id="g1">
		<columns>
			<column label="data" sort="auto"/>
		</columns>
	</grid>	
	<grid id="g2">
		<columns>
			<column label="value" sort="auto(value)"/>
			<column label="data" sort="auto"/>
		</columns>
	</grid>	
</window>
</zk>

package ctrl;

import java.util.*;

import org.zkoss.lang.Strings;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.*;

import test.Item;

public class Composer extends GenericForwardComposer {
	private Grid g1, g2;

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

		List<String> list = new ArrayList<String>();
		list.add("A");
		list.add("B");
		list.add("C");		
		List<Item> list2 = new ArrayList<Item>();
		list2.add(new Item(2, "a"));
		list2.add(new Item(1, "b"));
		list2.add(new Item(3, "c"));		
		ListModel model = new ListModelList(list);
		ListModel model2 = new ListModelList(list2);
		RowRenderer rowRenderer = new MyRowRenderer();
		g1.setModel(model);		
		g2.setModel(model2); 		
		g2.setRowRenderer(rowRenderer);
	}

	private class MyRowRenderer implements RowRenderer {
		public void render(Row row, Object data) {
			Item item = (Item) data;
			new Label(item.getValue() + "").setParent(row);
			new Label(item.getData()).setParent(row);
		}
	}
}