代码说明

package com.lh.innerclass;public class Sequence {	//使本接口定义外部化	static interface Selector{		//判断当前指针是否指向末尾		boolean end();		//返回当前指针指向的对象		Object current();		//指针移到下一位		void next();	}		//本成员变量被内部类无条件调用了	private Object[] items;		private int next;		public Sequence(int size) {		this.items = new Object[size];//		next = 0;	}		public void add(Object object){		if(this.next < this.items.length){			items[next++] = object;		}	}		//创建内部类的实例，返回给外部使用！	public Selector selector(){		return new SequenceSelector();	}		//内部类(私有)	private class SequenceSelector implements Selector{		private int i = 0;		public boolean end() {			return i == items.length;		}		public Object current() {			return items[i];		}		public void next() {			if(i < items.length){				i++;			}		}			}	//程序入口	public static void main(String[] args) {		int size = 10;		Sequence sequence = new Sequence(size);		Selector selector = sequence.selector();		for(int i = 0; i < size; i++){			sequence.add(i);		}				while(!selector.end()){			System.out.println(selector.current());			selector.next();		}	}}