Java设计模式之迭代器模式和组合模式

package com.whut.iterator;
import java.util.Iterator;

public  interface Menu {
public Iterator createIterator();
}

package com.whut.iterator;

import java.util.Iterator;

public class DinerMenu  implements Menu{

private static final int MAX_ITEMS=6;
private int numberOfItems=0;
private MenuItem[] menuItems;

public DinerMenu()
{
menuItems= new MenuItem[MAX_ITEMS];
addItem( "Dinner Vegetarian", "Bacon", true,2.99);
addItem( "Dinner BLT ", "Bacon BLT", false,2.99);
addItem( "Dinner hotdog", "A hot dog", false,3.48);
}

public void addItem(String name,String description, boolean vegetarian, double price)
{
MenuItem item= new MenuItem(name,description,vegetarian,price);
if(numberOfItems<MAX_ITEMS)
{
menuItems[numberOfItems]=item;
numberOfItems++;
}
else
System.out.println( "Sorry ,menu is full");
}

public Iterator createIterator()
{
return  new DinerMenuIterator(menuItems);
}


}

package com.whut.iterator;

import java.util.ArrayList;
import java.util.Iterator;
public class PancakeHouseMenu  implements Menu{

private ArrayList menuItems;

public PancakeHouseMenu()
{
menuItems= new ArrayList();
addItem( "K&B panckage breakfast", "pancakes with scramed eggs and toast", true,2.99);
addItem( "Regular panckage breakfast", "pancakes with fried eggs ", false,2.99);
addItem( "Blueberry breakfast", "pancakes made with fresh blueberry ", true,3.48);
addItem( "Waffles", "waffles, with your choice", true,3.59);
}

public void addItem(String name,String description, boolean vegetarian, double price)
{
MenuItem item= new MenuItem(name,description,vegetarian,price);
menuItems.add(item);
}
public Iterator createIterator()
{
return menuItems.iterator();
}
}

package com.whut.iterator;

import java.util.HashMap;
import java.util.Iterator;

public class CoffeeMenu  implements Menu{
private HashMap menuItems= new HashMap(); 
public CoffeeMenu()
{
addItem( "Coffee Burger" , "veggie burger on", true,3.99);
addItem( "Coffee Soup", "A cup of the soup", false,3.69);
addItem( "Coffee Burrito", "A large burrito", true,4.29);
}

public void addItem(String name,String description, boolean vegetarian, double price)
{
MenuItem item= new MenuItem(name,description,vegetarian,price);
menuItems.put(item.getName(),item);
}

@Override
public Iterator createIterator() {
// TODO Auto-generated method stub
//直接返回一个迭代器
return menuItems.values().iterator();
}
}

package com.whut.iterator;

import java.util.Iterator;

public class DinerMenuIterator  implements Iterator {

private MenuItem[] items;
private int position=0;//存放当前遍历的坐标

public DinerMenuIterator(MenuItem[] items)
{
this.items=items;
}

public  boolean hasNext() {
if(position>=items.length || items[position]== null)
return  false;
else
return  true;
}

public Object next() {
MenuItem menuItem=items[position];
position=position+1;
return menuItem;
}

public  void remove() {

if(position<=0)
throw  new IllegalStateException( "You can't remove an item at least");
if(items[position]!= null)
{
for( int i=position-1;i<items.length-1;i++)
items[i]=items[i+1];
items[items.length-1]= null;
}
}

}

package com.whut.iterator;
import java.util.Iterator;
public  class Waitress {

private Menu diner;
private Menu house;
private Menu cafe;
public Waitress(Menu diner,Menu house,Menu cafe)
{
this.diner=diner;
this.house=house;
this.cafe=cafe;
}

public void printMenu()
{
Iterator houseIterator=house.createIterator();
Iterator dinerIterator=diner.createIterator();
Iterator cafeIterator=cafe.createIterator();
System.out.println( "-------houseMenu--------");
printMenuItem(houseIterator);
System.out.println();

System.out.println( "-------dinnerMenu--------");
printMenuItem(dinerIterator);
System.out.println();

System.out.println( "-------coffeeMenu--------");
printMenuItem(cafeIterator);
}

private  void printMenuItem(Iterator iterator)
{
while(iterator.hasNext())
{
MenuItem menuItem=(MenuItem)iterator.next();
System.out.print(menuItem.getName()+ "_||_"+menuItem.getPrice()
+ "_||_"+menuItem.getDescription());
System.out.println();
}
}
}