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迭代器模式
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6 files changed

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‎src/com/anxpp/designpattern/iterator/ArrayList.java‎

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package com.anxpp.designpattern.iterator;
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//方便演示而实现的简陋的数组list
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public class ArrayList<T> implements List<T>{
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private int size; //存放的元素个数,会默认初始化为0
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private Object[] defaultList; //使用数组存放元素
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private static final int defaultLength = 10;//默认长度
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public ArrayList(){ //默认构造函数
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defaultList = new Object[defaultLength];
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}
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@Override
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public Iterator<T> iterator() {
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return new MyIterator();
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}
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//添加元素
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@Override
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public boolean add(T t) {
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if(size<=defaultLength){
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defaultList[size++] = t;
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return true;
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}
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return false;
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}
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//遍历器
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private class MyIterator implements Iterator<T>{
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private int next;
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@Override
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public boolean hasNext() {
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return next<size;
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}
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@SuppressWarnings("unchecked")
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@Override
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public T next() {
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return (T) defaultList[next++];
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}
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}
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}

‎src/com/anxpp/designpattern/iterator/Iterator.java‎

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package com.anxpp.designpattern.iterator;
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//只是需要遍历一堆数据，那么只需要2个方法就可以了
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public interface Iterator<T> {
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boolean hasNext(); //是否还有下一个元素
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T next(); //得到下一个元素
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}

‎src/com/anxpp/designpattern/iterator/LinkList.java‎

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package com.anxpp.designpattern.iterator;
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//方便演示而实现的简陋的单向链表list
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public class LinkList<T> implements List<T>{
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private int size; //存放的元素个数,会默认初始化为0
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private Node<T> first; //首节点，默认初始化为null
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@Override
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public Iterator<T> iterator() {
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return new MyIterator();
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}
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@Override
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public boolean add(T t) {
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if(size==0){
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first = new Node<T>(t,null);
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}
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while(first.next!=null);
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first.next = new Node<T>(t,null);
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return true;
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}
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//链表节点
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private static class Node<T>{
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T data;
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Node<T> next;
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Node(T data,Node<T> next){
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this.data = data;
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this.next = next;
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}
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}
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//遍历器
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private class MyIterator implements Iterator<T>{
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private Node<T> next; //下一个节点
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MyIterator(){
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next = first;
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}
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@Override
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public boolean hasNext() {
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return next!=null;
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}
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@Override
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public T next() {
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T data = next.data;
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next = next.next;
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return data;
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}
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}
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}

‎src/com/anxpp/designpattern/iterator/List.java‎

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package com.anxpp.designpattern.iterator;
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//便于介绍，不做多的操作
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public interface List<T> {
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Iterator<T> iterator(); //返回一个遍历器
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boolean add(T t); //添加元素到列表
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}

‎src/com/anxpp/designpattern/iterator/TestUse.java‎

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package com.anxpp.designpattern.iterator;
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public class TestUse {
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public static void main(String args[]){
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//分别定义两种结构
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List<Integer> array = new ArrayList<Integer>();
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List<Integer> link = new LinkList<Integer>();
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//添加数据
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for(int i = 1;i < 8; i++){
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array.add(i);
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link.add(i);
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}
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//获得迭代器
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Iterator<Integer> ai = array.iterator();
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Iterator<Integer> li = array.iterator();
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//遍历并输出
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while(ai.hasNext())
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System.out.print(ai.next());
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System.out.println();
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while(li.hasNext())
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System.out.print(li.next());
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}
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}

‎src/com/anxpp/designpattern/iterator/package-info.java‎

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/**
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* @author Administrator
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* 迭代器模式--此处未实现remove()方法
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*/
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package com.anxpp.designpattern.iterator;

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