泛型之工厂模式

public class Coffee
{
    private static long counter = 0;
   
    private final long id = counter++;
   
    public String toString()
    {
    return getClass().getSimpleName() + " " + id;   
    }
   
}


public class Americano extends Coffee {

}

public class Latte extends Coffee
{
   
}

public class Mocha extends Coffee
{

}

随机生成不同类型
import java.util.Iterator;
import java.util.Random;
/*
* 泛型接口  泛型实现的工厂模式
*/
public class CoffeeGenerator implements Generator<Coffee>,Iterable<Coffee>
{

    private Class[] types = {Latte.class,Mocha.class,Cappuccino.class,Americano.class};

    private static Random rand = new Random(15);
   
    public CoffeeGenerator(){}
   
    private int size = 0;
   
    public CoffeeGenerator(int sz) { size = sz;}

public Coffee next()
{
try
{
return (Coffee) types[rand.nextInt(types.length)].newInstance();
}
catch(Exception e)
{
throw new RuntimeException(e);
}
}

class CoffeeIterator implements Iterator<Coffee>
{
int count = size;
public boolean hasNext() {return count > 0;}
public Coffee next()
{
count--;
return CoffeeGenerator.this.next();
}
public void remove()
{
throw new UnsupportedOperationException();
}
};


public Iterator<Coffee> iterator()
{
return null;
}

public static void main(String [] args)
{
CoffeeGenerator gen = new CoffeeGenerator();

for (int i = 0; i < 5; i++)
    System.out.println(gen.next());

for(Coffee c : new CoffeeGenerator(5))
System.out.println(c);
}
   
}

同工厂模式对比，不需要传参