import java.util.Iterator;
import java.util.Random;

public class Test {
public static void main(String[] args) {
// ATester.test();
Tester.test();
}
}

interface Generator{
T next();
}

class A { }
class a extends A{ }
class b extends A{ }
class c extends A{ }
class d extends A{ }

/*
思路:
Generator这个生成器，你可以给它指定size，当你通过迭代器
调用它的生成方法时，你就只能生成你指定的size个元素。
*/
class ATester implements Generator,Iterable {

private Class\[\] types = {a.class,b.class,c.class,d.class};
private int size;
);

public ATester() {
}

public ATester(int size) {
    this.size = size;
}

@Override
public A next() {
    try{
        return (A)types\[rand.nextInt(types.length)\].newInstance();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (InstantiationException e) {
        e.printStackTrace();
    }
    return null;
}

@Override
public Iterator<A> iterator() {
    return new Iterator<A>() {
        int count = size;
        @Override
        public boolean hasNext() {
            ;
        }

        @Override
        public A next() {
            count--;
            return ATester.this.next();
        }
    };
}

static void test() {
    ATester g = new ATester();
    ; i < ; i++) {
        System.out.println(g.next());
    }
}

/*
负责生成斐波那契数列的生成器！
*/
class Fibonacci implements Generator {
,ppre=;
;
@Override
public Integer next() {
int result;

    i++;
     ) {
        result=;
    }else{
        result=pre+ppre;
    }

    ppre = pre;
    pre = result;

    return result;
}

}
//这个方案计算量太多了
class Fibonacci2 implements Generator {
;
private int fbi(int i) {
) {
;
}
)+fbi(i-);
}
@Override
public Integer next() {
return fbi(++count);
}
}

//编写一个适配器
class FibonacciAdaptor implements Iterable {
private int size;
private Fibonacci fibonacci;

public FibonacciAdaptor(int size, Fibonacci fibonacci) {
    this.size = size;
    this.fibonacci = fibonacci;
}

@Override
public Iterator<Integer> iterator() {
    return new Iterator<Integer>() {
        //我的方案，感觉没有书中的优雅
        //int i = 0;
        @Override
        public boolean hasNext() {
            //return i<size;
            ;
        }

        @Override
        public Integer next() {
            //i++;
            size--;
            return fibonacci.next();
        }
    };
}

}
class Tester{
static void test() {
Fibonacci f = new Fibonacci();
;
) {
System.out.print(f.next()+" ");
i++;
}
System.out.println();

    Fibonacci2 f2 = new Fibonacci2();
    i = ;
    ) {
        System.out.print(f2.next()+" ");
        i++;
    }

}

}