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组合模式:将对象聚合成树形结构来表现“整体/部分”的层次结构。

一、餐厅菜单项目

二、代码

1、超类MenuComponent

public abstract class MenuComponent {	public String getName() {		return "";	}	public String getDescription() {		return "";	}	public float getPrice() {		return 0;	}	public boolean isVegetable() {		return false;	}	public abstract void print();	public Iterator getIterator() {		return new NullIterator();	}}

2、CakeHouseMenu

public class CakeHouseMenu extends MenuComponent {	private ArrayList
   
     menuItems;	public CakeHouseMenu() {		menuItems = new ArrayList
    
     ();		addItem("KFC Cake Breakfast", "boiled eggs&toast&cabbage", true, 3.99f);		addItem("MDL Cake Breakfast", "fried eggs&toast", false, 3.59f);		addItem("Stawberry Cake", "fresh stawberry", true, 3.29f);		addItem("Regular Cake Breakfast", "toast&sausage", true, 2.59f);	}	private void addItem(String name, String description, boolean vegetable, float price) {		MenuItem menuItem = new MenuItem(name, description, vegetable, price);		menuItems.add(menuItem);	}	public Iterator getIterator() {		return new ComposeIterator(menuItems.iterator());	}	@Override	public void print() {		System.out.println("****This is CakeHouseMenu****");	};}
    
   

3、DinerMenu

public class DinerMenu extends MenuComponent {	private final static int Max_Items = 5;	private int numberOfItems = 0;	private MenuComponent[] menuItems;	public DinerMenu() {		menuItems = new MenuComponent[Max_Items];		addItem("vegetable Blt", "bacon&lettuce&tomato&cabbage", true, 3.58f);		addItem("Blt", "bacon&lettuce&tomato", false, 3.00f);		addItem("bean soup", "bean&potato salad", true, 3.28f);		addItem("hotdog", "onions&cheese&bread", false, 3.05f);		addSubMenu(new SubMenu());	}	private void addItem(String name, String description, boolean vegetable, float price) {		MenuItem menuItem = new MenuItem(name, description, vegetable, price);		if (numberOfItems >= Max_Items) {			System.err.println("sorry,menu is full!can not add another item");		} else {			menuItems[numberOfItems] = menuItem;			numberOfItems++;		}	}		private void addSubMenu(MenuComponent mMenuComponent) {		if (numberOfItems >= Max_Items) {			System.err.println("sorry,menu is full!can not add another item");		} else {			menuItems[numberOfItems] = mMenuComponent;			numberOfItems++;		}	}}

4、SubMenu

public class SubMenu extends MenuComponent {	private ArrayList
   
     menuItems;	public SubMenu() {		menuItems = new ArrayList
    
     ();		addItem("Apple Cookie", "Apple&candy&Cookie", true, 1.99f);		addItem("Banana Cookie", "Banana&candy&Cookie", false, 1.59f);		addItem("Orange Cookie", "Orange&Cookie", true, 1.29f);	}	private void addItem(String name, String description, boolean vegetable,float price) {		MenuItem menuItem = new MenuItem(name, description, vegetable, price);		menuItems.add(menuItem);	}	public Iterator getIterator() {		return new ComposeIterator(menuItems.iterator());	}	@Override	public void print() {		System.out.println("****This is SubMenu****");	};	}
    
   

5、MenuItem

public class MenuItem extends MenuComponent{	private String name,description;	private boolean vegetable;	private float price;	public MenuItem(String name,String description,boolean vegetable,float price){		this.name=name;		this.description=description;		this.vegetable=vegetable;		this.price=price;		}	@Override	public String getName()	{		return name;	}	@Override	public String getDescription()	{		return description;	}	@Override	public float getPrice()	{		return price;	}	@Override	public boolean  isVegetable()	{		return vegetable;	}	@Override	public void print() {		System.out.println(getName() + "***" + getPrice() + "***" + getDescription());	}}