shoppingcart.java

网上书店 。根据对网上书店系统的需求分析

package entity;

import java.io.Serializable;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

public class ShoppingCart implements Serializable {

	Map<String,CartItem> items = new HashMap<String,CartItem>();
	
	public ShoppingCart() {
	}

	//添加
	public void addItem(String key, Object product)
	{
		CartItem item = items.get( key );
		if( item == null )
		{
			items.put(key, new CartItem(product, 1));
		}
		else
		{
			item.setAmount( item.getAmount() + 1 );
		}
	}
	
	//更新数量
	public void updateAmount(String key, int amount)
	{
		if(amount < 1)
			return;
		//
		CartItem item = items.get( key );
		if( item != null )
		{
			item.setAmount( amount );
		}
	}
	
	//删除
	public void deleteItem(String key)
	{
		items.remove( key );
	}
	
	//清空
	public void clear()
	{
		items.clear();
	}
	
	//查看
	public Collection<CartItem> getItems()
	{
		return items.values();
	}
}