buysoap.java

以让某人去商店买肥皂为例

class Person
{
	private String name;
	private int money;
	
	public Person(String name,int money)
	{
		this.name=name;
		this.money=money;
	}
	public String getName()
	{
		return name;
	}
	public void move(String position)
	{
		System.out.println("come from "+name+": i have arrived "+position);
	}
	public int getMoney(int moneyCount)
	{
		if(moneyCount<money)
		{
			money=money-moneyCount;
			return moneyCount;
		}
		System.out.println("come from "+name+": i have not enough money.need "+moneyCount);
		return 0;
	}	
}


class Shop
{
	private String name ;
	
	Object [] content =new Object[100];
	
	public Shop(String name)
	{
		this.name=name;
	}
	
	public String getName()
	{
		return name;
	}
	
	public void buy(Object obj)
	{
		boolean flag = false;
		for(int i=0;i<content.length;i++)
		{
			if(content[i]==null)
			{
				content[i]=obj;
				flag=true;
				break;
			}
		}
		if(flag)
		{
			System.out.println("come form shop: buy success");
		}else
		{
			System.out.println("come form shop: the shop is full");
		}
	}
	public Object sell(String name)
	{
		if("soap".equals(name))
		{
			for(int i=0;i<content.length;i++)
			{
				if(content[i] instanceof Soap)
				{
					return content[i];
				}
			}
		}
		if("book".equals(name))
		{
			for(int i=0;i<content.length;i++)
			{
				if(content[i] instanceof Book)
				{
					return content[i];
				}
			}
		}
		return null;
	}
	
	public int getPrice(String name)
	{
		if("soap".equals(name))
		{
			for(int i=0;i<content.length;i++)
			{
				if(content[i] instanceof Soap)
				{
					return ((Soap)content[i]).getPrice();
				}
			}
		}
		if("book".equals(name))
		{
			for(int i=0;i<content.length;i++)
			{
				if(content[i] instanceof Book)
				{
					return ((Book)content[i]).getPrice();
				}
			}
		}
		System.out.println("come from "+name+": sorry,i have not");
		return -1;
	}	
}


class Soap
{
	private String name;
	private int price;
	public Soap(String name,int price)
	{
		this.name=name;
		this.price=price;
	}
	public String getName()
	{
		return name;
	}
	public int getPrice()
	{
		return price;
	}	
}

class Book
{
	private String name;
	private int price;
	public Book(String name,int price)
	{
		this.name=name;
		this.price=price;
	}
	public String getName()
	{
		return name;
	}
	public int getPrice()
	{
		return price;
	}
}

class TestBySoap
{
	public static void main(String [] args)
	{
		//找来一个人
		Person person = new Person("zs",200);
		//开了个商店
		Shop shop = new Shop("best store");		
		//商店进货
		shop.buy(new Soap("soft",20));
		shop.buy(new Book("java",300));
		//人去了商店
		person.move(shop.getName());
		//人问香皂价格
		int soapPrice = shop.getPrice("soap");
		//人取出钱
		if(person.getMoney(soapPrice)!=0)
		{
			//从商店得到香皂
			Soap soap = (Soap)shop.sell("soap");
			System.out.println("come from "+person.getName()+": i have got a soap,type is "+soap.getName()+" ,price is "+soap.getPrice());
		}
		
		
		
		int bookPrice = shop.getPrice("book");
		if(person.getMoney(bookPrice)!=0)
		{
			Book book = (Book)shop.sell("book");
			System.out.println("come from "+person.getName()+": i have got a book,type is "+book.getName()+" ,price is "+book.getPrice());
		}
	}
}