package com.pichen.dp.behavioralpattern.iterator;public interface Iterator {public Object first();public Object previous();public Object next();public boolean hasNext();}

package com.pichen.dp.behavioralpattern.iterator;import java.util.List;public class MyIterator implements Iterator{private List<Object> list;private int index = 0;public MyIterator(List<Object> list) {this.list = list;}@Overridepublic Object previous() {if((this.index - 1) < 0){return null;}else{return this.list.get(--index);}}@Overridepublic Object next() {if((this.index + 1) >= this.list.size()){return null;}else{return this.list.get(++index);}}@Overridepublic boolean hasNext() {if(this.index < (this.list.size() - 1)){return true;}return false;}/*** 〈一句话功能简述〉* 〈功能详细描述〉* @see com.pichen.dp.behavioralpattern.iterator.Iterator#first()* @return*/@Overridepublic Object first() {if(this.list.size() <= 0){return null;}else{return this.list.get(0);}}}

package com.pichen.dp.behavioralpattern.iterator;public abstract class Container {public abstract Iterator iterator();public abstract void put(Object obj);
}

package com.pichen.dp.behavioralpattern.iterator;import java.util.ArrayList;
import java.util.List;public class MyContainer extends Container{private List<Object> list;public MyContainer() {this.list = new ArrayList<Object>();}@Overridepublic void put(Object obj){this.list.add(obj);}@Overridepublic Iterator iterator() {return new MyIterator(list);}}

package com.pichen.dp.behavioralpattern.iterator;public class Main {public static void main(String[] args) {//创建一个自定义容器，直接使用ArrayList的实现，仅仅示例作用Container strContainer = new MyContainer();strContainer.put("001");strContainer.put("002");strContainer.put("003");Iterator myIterator = strContainer.iterator();//使用举例System.out.println("------------------next、hasNext示例------------------");System.out.println(myIterator.first());System.out.println(myIterator.next());System.out.println(myIterator.hasNext());System.out.println(myIterator.next());System.out.println(myIterator.hasNext());System.out.println(myIterator.next());System.out.println(myIterator.hasNext());//使用举例System.out.println("------------------previous、hasNext示例------------------");System.out.println(myIterator.previous());System.out.println(myIterator.previous());System.out.println(myIterator.previous());System.out.println(myIterator.hasNext());//使用迭代器遍历System.out.println("------------------迭代器遍历示例------------------");System.out.println(myIterator.first());while(myIterator.hasNext()){System.out.println(myIterator.next());}}
}

------------------next、hasNext示例------------------
001
002
true
003
false
null
false
------------------previous、hasNext示例------------------
002
001
null
true
------------------迭代器遍历示例------------------
001
002
003