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anxppanxpp
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迭代器模式
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8 files changed

+273
-101
lines changed

8 files changed

+273
-101
lines changed

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

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This file was deleted.

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

Lines changed: 0 additions & 45 deletions
This file was deleted.

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

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

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package com.anxpp.designpattern.iterator;
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import java.util.Arrays;
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//方便演示而实现的简陋的数组list
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public class MyArrayList<T> implements MyList<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 MyArrayList(){ //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 MyIterator<T> iterator() {
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return new Iterator();
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}
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//大小自动增长
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private void ensureCapacity(int capacity){
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int nowLength = defaultList.length;
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if(capacity >= nowLength){
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nowLength = nowLength + (nowLength>>1);
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if(nowLength<0)//溢出
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nowLength = Integer.MAX_VALUE;
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defaultList = Arrays.copyOf(defaultList, nowLength);
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}
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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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ensureCapacity(size+1);
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defaultList[size++] = t;
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return true;
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}
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//获取元素
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@SuppressWarnings("unchecked")
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@Override
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public T get(int index) {
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if(index<0 || index>=size) return null;
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return (T) defaultList[index];
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}
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@Override
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public T remove() {
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return remove(size-1);
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}
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@SuppressWarnings("unchecked")
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@Override
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public T remove(int index) {
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if(index<0||index>=size) return null;
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T element = (T) defaultList[index];
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if(index != size-1)
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System.arraycopy(defaultList, index+1, defaultList, index,size-index-1);
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size--;
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return element;
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}
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@Override
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public boolean remove(T element) {
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if(element==null){
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for(int i = 0 ; i<size;i++)
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if(defaultList[i]==null){
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System.arraycopy(defaultList, i+1, defaultList, i,size-i-1);
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size--;
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return true;
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}
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}
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else{
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for(int i = 0 ; i<size;i++)
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if(defaultList[i].equals(element)){
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System.arraycopy(defaultList, i+1, defaultList, i,size-i-1);
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size--;
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return true;
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}
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}
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return false;
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}
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@Override
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public boolean set(int index,T element) {
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if(index<0||index>=size) return false;
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defaultList[index] = element;
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return true;
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}
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@Override
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public int size() {
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return size;
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}
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//迭代器
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private class Iterator implements MyIterator<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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@Override
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public T remove() {
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// TODO Auto-generated method stub
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return null;
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}
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}
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}

src/com/anxpp/designpattern/iterator/Iterator.java renamed to src/com/anxpp/designpattern/iterator/MyIterator.java

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,8 @@
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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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public interface MyIterator<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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}
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T remove();
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}

‎src/com/anxpp/designpattern/iterator/MyLinkedList.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 MyLinkedList<T> implements MyList<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 MyIterator<T> iterator() {
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return new Iterator();
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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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size++;
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return true;
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}
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Node<T> node = first;
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while(node.next!=null)
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node = node.next;
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node.next = new Node<T>(t,null);
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size++;
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return true;
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}
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@Override
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public T get(int index) {
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Node<T> node = first;
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while(--index>=0)
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node = node.next;
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return node.data;
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}
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@Override
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public T remove() {
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return remove(size-1);
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}
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@Override
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public T remove(int index) {
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if(index<0||index>=size) return null;
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Node<T> node = first;
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while(--index>0)
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node = node.next;
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T element = node.next.data;
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node.next = node.next.next;
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size--;
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return element;
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}
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@Override
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public boolean remove(T element) {
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if(element == null){
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if(first.data==null){
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first = first.next;
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size--;
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return true;
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}
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Node<T> node = first;
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do{
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if(node.next.data==null){
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node.next = node.next.next;
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size--;
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return true;
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}
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node = node.next;
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}
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while(node.next!=null);
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}
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else{
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if(first.data.equals(element)){
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first = first.next;
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size--;
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return true;
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}
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Node<T> node = first;
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do{
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if(node.next.data.equals(element)){
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node.next = node.next.next;
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size--;
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return true;
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}
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node = node.next;
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}
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while(node.next!=null);
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}
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return false;
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}
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@Override
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public boolean set(int index, T element) {
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if(index<0||index>=size) return false;
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Node<T> node = first;
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while(--index>0)
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node = node.next;
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node.data = element;
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return true;
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}
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@Override
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public int size() {
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return size;
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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 Iterator implements MyIterator<T>{
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private Node<T> next; //下一个节点
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Iterator(){
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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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@Override
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public T remove() {
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// TODO Auto-generated method stub
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return null;
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}
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}
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}

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

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package com.anxpp.designpattern.iterator;
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//集合接口
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public interface MyList<T> {
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MyIterator<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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T get(int index); //得到元素
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T remove(); //删除最后一个元素
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boolean remove(T element); //删除指定元素
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T remove(int index); //删除指定位置元素
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boolean set(int index,T element); //修改指定位置值
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int size();
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}

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