package test;

import java.util.Comparator;
import java.util.List;

import org.zkoss.zul.GroupsModelArray;

public class MyGroupModel<D, H, F, E> extends GroupsModelArray<D, H, F, E> {
	
	public MyGroupModel(List<D> data, Comparator<D> cmpr) {
		super(data, cmpr, 0);
	}
	
	protected H createGroupHead(D[] groupdata, int index, int col) {
		
		return (H)new Object[] { groupdata[0], new Integer(col) };
	}
}

<zk>
    <zscript><![CDATA[
		import java.util.Calendar;
		import java.text.DateFormat;
		import java.text.SimpleDateFormat;
		import org.zkoss.lang.reflect.Fields;
		
		public class SampleBean {
			private String name;
			private int number;
			private Date date;

			public SampleBean(String name, int number, Date date) {
				super();
				this.name = name;
				this.number = number;
				this.date = date;
			}

			public String getName() {
				return name;
			}

			public void setName(String name) {
				this.name = name;
			}

			public int getNumber() {
				return number;
			}

			public void setNumber(int number) {
				this.number = number;
			}

			public Date getDate() {
				return date;
			}

			public void setDate(Date date) {
				this.date = date;
			}
		}
		
		
		int count = 10;
		
		List list = new ArrayList(count);
		Random rand = new Random(new Random().nextLong());
		
		Calendar cal = Calendar.getInstance();
		for (int i = 0; i < count; i++) {
			list.add(new SampleBean("item " + rand.nextInt(count),
					rand.nextInt(count), cal.getTime()));
			cal.add(Calendar.DAY_OF_MONTH, 1);
		}
		
		GroupsModelArray model = 
			new test.MyGroupModel(list, new FieldComparator("name", true));
		
		DateFormat df = new SimpleDateFormat("yyyy/MM/dd");
		
		RowRenderer renderer = new RowRenderer() {
			public void render(Row row, Object data, int index) {
				if (row instanceof Group) {
					Object[] obj = (Object[]) data; // prepared by
					// createGroupHead()
					row.appendChild(new Label(
							getGroupHead(row, (SampleBean) obj[0], ((Integer) obj[1]).intValue())));
				} else {
					SampleBean b = (SampleBean) data;
					row.appendChild(new Label(b.getName()));
					row.appendChild(new Label(b.getNumber()+""));
					row.appendChild(new Label(df.format(b.getDate())));
				}
			}
			
			private String getGroupHead(Row row, SampleBean bean, int index) {
				Column column = 
					(Column) row.getGrid().getColumns().getChildren().get(index);
				String field =  //print: category
					((FieldComparator) column.getSortAscending()).getRawOrderBy();
				try {
					return Fields.get(bean, field).toString();
				} catch (NoSuchMethodException ex) {
					throw UiException.Aide.wrap(ex);
				}
			}
		};
    ]]></zscript>
    
    <grid model="${model}" rowRenderer="${renderer}">
    	<columns menupopup="auto">
    		<column label="name" sort="auto(name)"/>
    		<column label="number" sort="auto(number)"/>
    		<column label="date" sort="auto(date)"/>
    	</columns>
    </grid>
</zk>