<window apply="pkg$.TestComposer">
    <listbox id="listbox">
        <listhead>
            <listheader label="Category" />
            <listheader label="Name" />
            <listheader label="Top Nutrients" />
        </listhead>
    </listbox>
</window>

package pkg$;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Set;

import pkg$.TestComposer.FoodGroupModel.FoodGroupInfo;

import org.zkoss.zk.ui.event.SelectEvent;
import org.zkoss.zk.ui.select.SelectorComposer;
import org.zkoss.zk.ui.select.annotation.Listen;
import org.zkoss.zk.ui.select.annotation.Wire;
import org.zkoss.zul.GroupComparator;
import org.zkoss.zul.GroupsModelArray;
import org.zkoss.zul.Label;
import org.zkoss.zul.ListModelArray;
import org.zkoss.zul.Listbox;
import org.zkoss.zul.Listcell;
import org.zkoss.zul.Listgroup;
import org.zkoss.zul.Listgroupfoot;
import org.zkoss.zul.Listheader;
import org.zkoss.zul.Listitem;
import org.zkoss.zul.ListitemRenderer;
import org.zkoss.zul.Window;

@SuppressWarnings("serial")
public class TestComposer extends SelectorComposer<Window> {
    
    static class Food {
        private String category;
        private String name;
        private String topNutrients;
        
        public Food(String category, String name, String topNutrients) {
            setCategory(category);
            setName(name);
            setTopNutrients(topNutrients);
        }

        public String getCategory() {
            return category;
        }
        public void setCategory(String category) {
            this.category = category;
        }
        
        public String getName() {
            return name;
        }
        public void setName(String name) {
            this.name = name;
        }
        
        public String getTopNutrients() {
            return topNutrients;
        }
        public void setTopNutrients(String topNutrients) {
            this.topNutrients = topNutrients;
        }
    }
    
    static class FoodData {
        private static List<Food> foods = new ArrayList<Food>();
        static {
            foods.add(new Food("Vegetables", "Asparagus", "Vitamin K"));
            foods.add(new Food("Vegetables", "Beets", "Folate"));
            foods.add(new Food("Seafood", "Salmon", "Tryptophan"));
            foods.add(new Food("Seafood", "Shrimp", "Tryptophan"));
        }
        
        public static List<Food> getAllFoods() {
            return foods;
        }       
    }
    
    static class FoodGroupComparator implements GroupComparator<Food> {
        public int compareGroup(Food food1, Food food2) {
            return Math.abs(compare(food1, food2));
        }

        public int compare(Food food1, Food food2) {
            return food1.getCategory().compareTo(food2.getCategory());
        }
    }
    
    static class FoodGroupModel extends GroupsModelArray<Food, FoodGroupModel.FoodGroupInfo, Object, Object> {
        public FoodGroupModel(Food[] data, Comparator<Food> compr) {
            super(data, compr);
        }
        
        protected FoodGroupInfo createGroupHead(Food[] groupData, int index, int column) {
            return new FoodGroupInfo(groupData[0], index, column);
        }
        
        protected Object createGroupFoot(Food[] groupData, int index, int column) {
            return groupData.length;
        }
        
        static class FoodGroupInfo {
            private Food firstChild;
            private int groupIndex;
            private int columnIndex;
            
            public FoodGroupInfo(Food firstChild, int groupIndex, int columnIndex) {
                this.firstChild = firstChild;
                this.groupIndex = groupIndex;
                this.columnIndex = columnIndex;
            }

            public Food getFirstChild() {
                return firstChild;
            }
            public int getGroupIndex() {
                return groupIndex;
            }
            public int getColumnIndex() {
                return columnIndex;
            }
        }
    }
    
    static class FoodGroupRenderer implements ListitemRenderer<Object> {
        public void render(Listitem item, Object obj, int index) throws Exception {
            if (item instanceof Listgroup) {
                FoodGroupInfo groupInfo = (FoodGroupInfo) obj;
                Food food = groupInfo.getFirstChild();
                String groupTxt;
                switch (groupInfo.getColumnIndex()) {
                case 0:
                    groupTxt = food.getCategory();
                    break;
                case 1:
                    groupTxt = food.getName();
                    break;
                case 2:
                    groupTxt = food.getTopNutrients();
                    break;
                default:
                    groupTxt = food.getCategory();
                }
                item.appendChild(new Listcell(groupTxt));
                item.setValue(obj);
            } else if (item instanceof Listgroupfoot) {
                Listcell cell = new Listcell();
                cell.appendChild(new Label("Total " + obj + " Items"));
                cell.setSpan(3);
                item.appendChild(cell);
            } else {
                Food data = (Food) obj;
                item.appendChild(new Listcell(data.getCategory()));
                item.appendChild(new Listcell(data.getName()));
                item.appendChild(new Listcell(data.getTopNutrients()));
                item.setValue(data);
            }
        }
    }
    
    @Wire
    private Listbox listbox;
    
    private GroupsModelArray<Food, FoodGroupInfo, Object, Object> groupModel;
    
    private ListitemRenderer<Object> groupRenderer = new FoodGroupRenderer();

    @Override
    public void doAfterCompose(Window comp) throws Exception {
        super.doAfterCompose(comp);
        org.zkoss.lang.Library.setProperty("org.zkoss.zul.listbox.rod","false");

        Food[] foods = FoodData.getAllFoods().toArray(new Food[] {});
        groupModel = new FoodGroupModel(foods, new FoodGroupComparator());
        groupModel.setMultiple(true);
        for (Food food : foods)
            groupModel.addToSelection(food);

        listbox.setCheckmark(true);
        listbox.setModel(groupModel);
        listbox.setItemRenderer(groupRenderer);        
    }    
}