-
Notifications
You must be signed in to change notification settings - Fork 19
/
CopyOnWriteArrayList源码解析.html
1 lines (1 loc) · 51.9 KB
/
CopyOnWriteArrayList源码解析.html
1
<!-- build time:Wed Mar 09 2022 10:17:45 GMT+0800 (GMT+08:00) --><!doctype html><html class="theme-next mist" lang="zh-Hans"><head><meta name="generator" content="Hexo 3.8.0"><meta name="google-site-verification" content="7Tau9WyVgxnsEY9oYedu9g0U6_8akOX3wiKbaYcrg9A"><meta name="baidu-site-verification" content="EVwLiaxdxX"><link href="/css/xps13.css" rel="stylesheet" type="text/css"><link href="/css/message.css" rel="stylesheet" type="text/css"><link href="//fonts.googleapis.com/css?family=Baloo+Bhaijaan|Inconsolata|Josefin+Sans|Montserrat" rel="stylesheet"><script type="text/javascript" src="/js/jquery-1.11.3.min.js"></script><meta charset="UTF-8"><meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1"><meta http-equiv="Cache-Control" content="no-transform"><meta http-equiv="Cache-Control" content="no-siteapp"><link href="/lib/font-awesome/css/font-awesome.min.css?v=4.6.2" rel="stylesheet" type="text/css"><link href="/css/main.css?v=5.1.1" rel="stylesheet" type="text/css"><meta name="keywords" content="Java,"><link rel="alternate" href="/atom.xml" title="MrBird" type="application/atom+xml"><link rel="shortcut icon" type="image/x-icon" href="/bird.png?v=5.1.1"><meta name="description" content="CopyOnWriteArrayList为线程安全的ArrayList，这节分析下CopyOnWriteArrayList的源码，基于JDK1.8。"><meta name="keywords" content="Java"><meta property="og:type" content="article"><meta property="og:title" content="CopyOnWriteArrayList源码解析"><meta property="og:url" content="http://mrbird.cc/CopyOnWriteArrayList源码解析.html"><meta property="og:site_name" content="MrBird"><meta property="og:description" content="CopyOnWriteArrayList为线程安全的ArrayList，这节分析下CopyOnWriteArrayList的源码，基于JDK1.8。"><meta property="og:locale" content="zh-Hans"><meta property="og:image" content="http://mrbird.cc/img/[email protected]"><meta property="og:updated_time" content="2021-02-22T03:19:30.011Z"><meta name="twitter:card" content="summary"><meta name="twitter:title" content="CopyOnWriteArrayList源码解析"><meta name="twitter:description" content="CopyOnWriteArrayList为线程安全的ArrayList，这节分析下CopyOnWriteArrayList的源码，基于JDK1.8。"><meta name="twitter:image" content="http://mrbird.cc/img/[email protected]"><script type="text/javascript" id="hexo.configurations">var NexT=window.NexT||{},CONFIG={root:"/",scheme:"Mist",sidebar:{position:"left",display:"always",offset:12,offset_float:0,b2t:!1,scrollpercent:!0},fancybox:!1,motion:!1}</script><title>CopyOnWriteArrayList源码解析 | MrBird</title></head><body ondragstart="return!1" class="animsition" lang="zh-Hans" style="overflow-x:hidden;padding-left:280px"><script type="text/javascript" src="/js/mo.min.js"></script><style>body{text-rendering:geometricPrecision!important;font-family:'Josefin Sans','PingFang SC'!important;-webkit-font-smoothing:antialiased!important;-webkit-text-size-adjust:100%!important;background-color:#f4f6f7}@media (min-width:768px) and (max-width:991px){body .header-innerr{width:700px!important}}.header-innerr{margin:0 auto;padding:100px 0 70px;width:880px}@media (min-width:1600px){.container .header-innerr{width:996px}}.header-innerr{position:relative}.header-innerr{padding:0}.header-innerr:after,.header-innerr:before{content:" ";display:table}.header-innerr:after{clear:both}@media (max-width:767px){.header-innerr{width:auto;padding:10px;margin-bottom:-20px}}</style><div class="container sidebar-position-left page-post-detail"><div class="headband"></div><header id="header" class="header"><div class="header-inner"><div class="site-brand-wrapper"><div class="site-meta"><link href="https://fonts.font.im/css?family=Merienda" rel="stylesheet"><div class="custom-logo-site-title"></div><h1 class="site-subtitle" itemprop="description"></h1></div><div class="site-nav-toggle"><button><span class="btn-bar"></span> <span class="btn-bar"></span> <span class="btn-bar"></span></button></div></div><nav class="site-nav"><div class="site-search"><div class="popup search-popup local-search-popup"><div class="local-search-header clearfix"><span class="search-icon"><i class="fa fa-search"></i> </span><span class="popup-btn-close"><i class="fa fa-times-circle"></i></span><div class="local-search-input-wrapper"><input autocomplete="off" placeholder="Search" spellcheck="false" type="text" id="local-search-input"></div></div><div id="local-search-result"></div></div></div></nav></div><div class="header-innerr"></div></header><main id="main" class="main"><div class="main-inner"><div class="content-wrap"><div id="content" class="content"><div id="posts" class="posts-expand"><article class="post post-type-normal" itemscope itemtype="http://schema.org/Article"><link itemprop="mainEntityOfPage" href="http://mrbird.cc/CopyOnWriteArrayList源码解析.html"><span hidden itemprop="author" itemscope itemtype="http://schema.org/Person"><meta itemprop="name" content="MrBird"><meta itemprop="description" content=""><meta itemprop="image" content="/images/blogImage.jpg"></span><span hidden itemprop="publisher" itemscope itemtype="http://schema.org/Organization"><meta itemprop="name" content="MrBird"></span><header class="post-header"><h2 class="post-title" itemprop="name headline">CopyOnWriteArrayList源码解析</h2><div class="post-meta"><span class="post-time"><span class="post-meta-item-icon"><i class="fa fa-calendar-o"></i> </span><span class="post-meta-item-text"></span> <time title="创建于" itemprop="dateCreated datePublished" datetime="2020-08-18T11:23:44+08:00">2020-08-18 </time></span><span></span> <span class="post-meta-divider">|</span> <span class="page-pv"><i class="fa fa-laptop"></i> Visit count <span class="busuanzi-value" id="busuanzi_value_page_pv"></span></span></div></header><div class="post-body" itemprop="articleBody"><p>CopyOnWriteArrayList为线程安全的ArrayList，这节分析下CopyOnWriteArrayList的源码，基于JDK1.8。<a id="more"></a></p><h2 id="类结构"><a href="#类结构" class="headerlink" title="类结构"></a>类结构</h2><p>CopyOnWriteArrayList类关系图：</p><p><img src="img/[email protected]" alt="QQ20210222-095256@2x"></p><p>CopyOnWriteArrayList实现了List接口的所有方法，主要包含如下两个成员变量：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// 可重入锁，用于对写操作加锁</span></span><br><span class="line"><span class="keyword">final</span> <span class="keyword">transient</span> ReentrantLock lock = <span class="keyword">new</span> ReentrantLock();</span><br><span class="line"></span><br><span class="line"><span class="comment">// Object类型数组，存放数据，volatile修饰，目的是一个线程对这个字段的修改另外一个线程立即可见</span></span><br><span class="line"><span class="keyword">private</span> <span class="keyword">transient</span> <span class="keyword">volatile</span> Object[] array;</span><br></pre></td></tr></table></figure><p></p><p>CopyOnWriteArrayList中并没有和容量有关的属性或者常量，下面通过对一些常用方法的源码解析，就可以知道原因。</p><h2 id="方法解析"><a href="#方法解析" class="headerlink" title="方法解析"></a>方法解析</h2><h3 id="构造函数"><a href="#构造函数" class="headerlink" title="构造函数"></a>构造函数</h3><p><code>CopyOnWriteArrayList()</code>空参构造函数：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="title">CopyOnWriteArrayList</span><span class="params">()</span> </span>{</span><br><span class="line"> setArray(<span class="keyword">new</span> Object[<span class="number">0</span>]);</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="function"><span class="keyword">final</span> <span class="keyword">void</span> <span class="title">setArray</span><span class="params">(Object[] a)</span> </span>{</span><br><span class="line"> array = a;</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><p>无参构造函数直接创建了一个长度为0的Object数组。</p><p><code>CopyOnWriteArrayList(Collection<? extends E> c)</code>：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="title">CopyOnWriteArrayList</span><span class="params">(Collection<? extends E> c)</span> </span>{</span><br><span class="line"> Object[] elements;</span><br><span class="line"> <span class="keyword">if</span> (c.getClass() == CopyOnWriteArrayList.class)</span><br><span class="line"> <span class="comment">// 如果集合类型就是CopyOnWriteArrayList，则直接将其array赋值给当前CopyOnWriteArrayList</span></span><br><span class="line"> elements = ((CopyOnWriteArrayList<?>)c).getArray();</span><br><span class="line"> <span class="keyword">else</span> {</span><br><span class="line"> <span class="comment">// 如果不是CopyOnWriteArrayList类型，则将集合转换为数组</span></span><br><span class="line"> elements = c.toArray();</span><br><span class="line"> <span class="comment">// 就如ArrayList源码分析所述那样，c.toArray()返回类型不一定是Object[].class，所以需要转换</span></span><br><span class="line"> <span class="keyword">if</span> (elements.getClass() != Object[].class)</span><br><span class="line"> elements = Arrays.copyOf(elements, elements.length, Object[].class);</span><br><span class="line"> }</span><br><span class="line"> <span class="comment">// 设置array值</span></span><br><span class="line"> setArray(elements);</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><p><code>CopyOnWriteArrayList(E[] toCopyIn)</code>：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="title">CopyOnWriteArrayList</span><span class="params">(E[] toCopyIn)</span> </span>{</span><br><span class="line"> <span class="comment">// 入参为数组，拷贝一份赋值给array</span></span><br><span class="line"> setArray(Arrays.copyOf(toCopyIn, toCopyIn.length, Object[].class));</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><h3 id="add-E-e"><a href="#add-E-e" class="headerlink" title="add(E e)"></a>add(E e)</h3><p><code>add(E e)</code>往CopyOnWriteArrayList末尾添加元素：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="keyword">boolean</span> <span class="title">add</span><span class="params">(E e)</span> </span>{</span><br><span class="line"> <span class="comment">// 获取可重入锁</span></span><br><span class="line"> <span class="keyword">final</span> ReentrantLock lock = <span class="keyword">this</span>.lock;</span><br><span class="line"> <span class="comment">// 上锁，同一时间内只能有一个线程进入</span></span><br><span class="line"> lock.lock();</span><br><span class="line"> <span class="keyword">try</span> {</span><br><span class="line"> <span class="comment">// 获取当前array属性值</span></span><br><span class="line"> Object[] elements = getArray();</span><br><span class="line"> <span class="comment">// 获取当前array数组长度</span></span><br><span class="line"> <span class="keyword">int</span> len = elements.length;</span><br><span class="line"> <span class="comment">// 复制一份新数组，新数组长度为当前array数组长度+1</span></span><br><span class="line"> Object[] newElements = Arrays.copyOf(elements, len + <span class="number">1</span>);</span><br><span class="line"> <span class="comment">// 在新数组末尾添加元素</span></span><br><span class="line"> newElements[len] = e;</span><br><span class="line"> <span class="comment">// 新数组赋值给array属性</span></span><br><span class="line"> setArray(newElements);</span><br><span class="line"> <span class="keyword">return</span> <span class="keyword">true</span>;</span><br><span class="line"> } <span class="keyword">finally</span> {</span><br><span class="line"> <span class="comment">// 锁释放</span></span><br><span class="line"> lock.unlock();</span><br><span class="line"> }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="keyword">final</span> Object[] getArray() {</span><br><span class="line"> <span class="keyword">return</span> array;</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><p>可以看到，add操作通过ReentrantLock来确保线程安全。通过add方法，我们也可以看出CopyOnWriteArrayList修改操作的基本思想为：复制一份新的数组，新数组长度刚好能够容纳下需要添加的元素；在新数组里进行操作；最后将新数组赋值给array属性，替换旧数组。这种思想也称为“写时复制”，所以称为CopyOnWriteArrayList。</p><p>此外，我们可以看到CopyOnWriteArrayList中并没有类似于ArrayList的grow方法扩容的操作。</p><h3 id="add-int-index-E-element"><a href="#add-int-index-E-element" class="headerlink" title="add(int index, E element)"></a>add(int index, E element)</h3><p><code>add(int index, E element)</code>指定下标添加指定元素：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="keyword">void</span> <span class="title">add</span><span class="params">(<span class="keyword">int</span> index, E element)</span> </span>{</span><br><span class="line"> <span class="comment">// 获取可重入锁</span></span><br><span class="line"> <span class="keyword">final</span> ReentrantLock lock = <span class="keyword">this</span>.lock;</span><br><span class="line"> <span class="comment">// 上锁，同一时间内只能有一个线程进入</span></span><br><span class="line"> lock.lock();</span><br><span class="line"> <span class="keyword">try</span> {</span><br><span class="line"> <span class="comment">// 获取当前array属性值</span></span><br><span class="line"> Object[] elements = getArray();</span><br><span class="line"> <span class="comment">// 获取当前array数组长度</span></span><br><span class="line"> <span class="keyword">int</span> len = elements.length;</span><br><span class="line"> <span class="comment">// 下标检查</span></span><br><span class="line"> <span class="keyword">if</span> (index > len || index < <span class="number">0</span>)</span><br><span class="line"> <span class="keyword">throw</span> <span class="keyword">new</span> IndexOutOfBoundsException(<span class="string">"Index: "</span>+index+</span><br><span class="line"> <span class="string">", Size: "</span>+len);</span><br><span class="line"> Object[] newElements;</span><br><span class="line"> <span class="keyword">int</span> numMoved = len - index;</span><br><span class="line"> <span class="keyword">if</span> (numMoved == <span class="number">0</span>)</span><br><span class="line"> <span class="comment">// numMoved为0，说明是在末尾添加，过程和add(E e)方法一致</span></span><br><span class="line"> newElements = Arrays.copyOf(elements, len + <span class="number">1</span>);</span><br><span class="line"> <span class="keyword">else</span> {</span><br><span class="line"> <span class="comment">// 否则创建一个新数组，数组长度为旧数组长度值+1</span></span><br><span class="line"> newElements = <span class="keyword">new</span> Object[len + <span class="number">1</span>];</span><br><span class="line"> <span class="comment">// 分两次复制，分别将index之前和index+1之后的元素复制到新数组中</span></span><br><span class="line"> System.arraycopy(elements, <span class="number">0</span>, newElements, <span class="number">0</span>, index);</span><br><span class="line"> System.arraycopy(elements, index, newElements, index + <span class="number">1</span>,</span><br><span class="line"> numMoved);</span><br><span class="line"> }</span><br><span class="line"> <span class="comment">// 在新数组的index位置添加指定元素</span></span><br><span class="line"> newElements[index] = element;</span><br><span class="line"> <span class="comment">// 新数组赋值给array属性，替换旧数组</span></span><br><span class="line"> setArray(newElements);</span><br><span class="line"> } <span class="keyword">finally</span> {</span><br><span class="line"> <span class="comment">// 锁释放</span></span><br><span class="line"> lock.unlock();</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><h3 id="set-int-index-E-element"><a href="#set-int-index-E-element" class="headerlink" title="set(int index, E element)"></a>set(int index, E element)</h3><p><code>set(int index, E element)</code>设置指定位置的值：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> E <span class="title">set</span><span class="params">(<span class="keyword">int</span> index, E element)</span> </span>{</span><br><span class="line"> <span class="comment">// 获取可重入锁</span></span><br><span class="line"> <span class="keyword">final</span> ReentrantLock lock = <span class="keyword">this</span>.lock;</span><br><span class="line"> <span class="comment">// 上锁，同一时间内只能有一个线程进入</span></span><br><span class="line"> lock.lock();</span><br><span class="line"> <span class="keyword">try</span> {</span><br><span class="line"> <span class="comment">// 获取当前array属性值</span></span><br><span class="line"> Object[] elements = getArray();</span><br><span class="line"> <span class="comment">// 获取当前array指定index下标值</span></span><br><span class="line"> E oldValue = get(elements, index);</span><br><span class="line"> <span class="keyword">if</span> (oldValue != element) {</span><br><span class="line"> <span class="comment">// 如果新值和旧值不相等</span></span><br><span class="line"> <span class="keyword">int</span> len = elements.length;</span><br><span class="line"> <span class="comment">// 复制一份新数组，长度和旧数组一致</span></span><br><span class="line"> Object[] newElements = Arrays.copyOf(elements, len);</span><br><span class="line"> <span class="comment">// 修改新数组index下标值</span></span><br><span class="line"> newElements[index] = element;</span><br><span class="line"> <span class="comment">// 新数组赋值给array属性，替换旧数组</span></span><br><span class="line"> setArray(newElements);</span><br><span class="line"> } <span class="keyword">else</span> {</span><br><span class="line"> <span class="comment">// 即使新值和旧值一致，为了确保volatile语义，需要重新设置array</span></span><br><span class="line"> setArray(elements);</span><br><span class="line"> }</span><br><span class="line"> <span class="keyword">return</span> oldValue;</span><br><span class="line"> } <span class="keyword">finally</span> {</span><br><span class="line"> <span class="comment">// 释放锁</span></span><br><span class="line"> lock.unlock();</span><br><span class="line"> }</span><br><span class="line">}</span><br><span class="line"></span><br><span class="line"><span class="function"><span class="keyword">private</span> E <span class="title">get</span><span class="params">(Object[] a, <span class="keyword">int</span> index)</span> </span>{</span><br><span class="line"> <span class="keyword">return</span> (E) a[index];</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><h3 id="remove-int-index"><a href="#remove-int-index" class="headerlink" title="remove(int index)"></a>remove(int index)</h3><p><code>remove(int index)</code>删除指定下标元素：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> E <span class="title">remove</span><span class="params">(<span class="keyword">int</span> index)</span> </span>{</span><br><span class="line"> <span class="comment">// 获取可重入锁</span></span><br><span class="line"> <span class="keyword">final</span> ReentrantLock lock = <span class="keyword">this</span>.lock;</span><br><span class="line"> <span class="comment">// 上锁，同一时间内只能有一个线程进入</span></span><br><span class="line"> <span class="keyword">try</span> {</span><br><span class="line"> <span class="comment">// 获取当前array属性值</span></span><br><span class="line"> Object[] elements = getArray();</span><br><span class="line"> <span class="comment">// 获取当前array长度</span></span><br><span class="line"> <span class="keyword">int</span> len = elements.length;</span><br><span class="line"> <span class="comment">// 获取旧值</span></span><br><span class="line"> E oldValue = get(elements, index);</span><br><span class="line"> <span class="keyword">int</span> numMoved = len - index - <span class="number">1</span>;</span><br><span class="line"> <span class="keyword">if</span> (numMoved == <span class="number">0</span>)</span><br><span class="line"> <span class="comment">// 如果删除的是最后一个元素，则将当前array设置为新数组</span></span><br><span class="line"> <span class="comment">// 新数组长度为旧数组长度-1，这样刚好截去了最后一个元素</span></span><br><span class="line"> setArray(Arrays.copyOf(elements, len - <span class="number">1</span>));</span><br><span class="line"> <span class="keyword">else</span> {</span><br><span class="line"> <span class="comment">// 分段复制，将index前的元素和index+1后的元素复制到新数组</span></span><br><span class="line"> <span class="comment">// 新数组长度为旧数组长度-1</span></span><br><span class="line"> Object[] newElements = <span class="keyword">new</span> Object[len - <span class="number">1</span>];</span><br><span class="line"> System.arraycopy(elements, <span class="number">0</span>, newElements, <span class="number">0</span>, index);</span><br><span class="line"> System.arraycopy(elements, index + <span class="number">1</span>, newElements, index,</span><br><span class="line"> numMoved);</span><br><span class="line"> <span class="comment">// 设置array</span></span><br><span class="line"> setArray(newElements);</span><br><span class="line"> }</span><br><span class="line"> <span class="keyword">return</span> oldValue;</span><br><span class="line"> } <span class="keyword">finally</span> {</span><br><span class="line"> <span class="comment">// 锁释放</span></span><br><span class="line"> lock.unlock();</span><br><span class="line"> }</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><div class="note info">可以看到，CopyOnWriteArrayList中的增删改操作都是在新数组中进行的，并且通过加锁的方式确保同一时刻只能有一个线程进行操作，操作完后赋值给array属性，替换旧数组，旧数组失去了引用，最终由GC回收。</div><h3 id="get-int-index"><a href="#get-int-index" class="headerlink" title="get(int index)"></a>get(int index)</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> E <span class="title">get</span><span class="params">(<span class="keyword">int</span> index)</span> </span>{</span><br><span class="line"> <span class="keyword">return</span> get(getArray(), index);</span><br><span class="line">}</span><br><span class="line"><span class="keyword">final</span> Object[] getArray() {</span><br><span class="line"> <span class="keyword">return</span> array;</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p>可以看到，<code>get(int index)</code>操作是分两步进行的：</p><ol><li>通过<code>getArray()</code>获取array属性值；</li><li>获取array数组index下标值。</li></ol><p>这个过程并没有加锁，所以在并发环境下可能出现如下情况：</p><ol><li>线程1调用<code>get(int index)</code>方法获取值，内部通过<code>getArray()</code>方法获取到了array属性值；</li><li>线程2调用CopyOnWriteArrayList的增删改方法，内部通过<code>setArray</code>方法修改了array属性的值；</li><li>线程1还是从旧的array数组中取值。</li></ol><p><strong>所以<code>get</code>方法是弱一致性的</strong>。</p><h3 id="size"><a href="#size" class="headerlink" title="size()"></a>size()</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> <span class="keyword">int</span> <span class="title">size</span><span class="params">()</span> </span>{</span><br><span class="line"> <span class="keyword">return</span> getArray().length;</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p><code>size()</code>方法返回当前array属性长度，因为CopyOnWriteArrayList中的array数组每次复制都刚好能够容纳下所有元素，并不像ArrayList那样会预留一定的空间。所以CopyOnWriteArrayList中并没有size属性，元素的个数和数组的长度是相等的。</p><h3 id="迭代器"><a href="#迭代器" class="headerlink" title="迭代器"></a>迭代器</h3><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">public</span> Iterator<E> <span class="title">iterator</span><span class="params">()</span> </span>{</span><br><span class="line"> <span class="keyword">return</span> <span class="keyword">new</span> COWIterator<E>(getArray(), <span class="number">0</span>);</span><br><span class="line">}</span><br><span class="line"><span class="keyword">static</span> <span class="keyword">final</span> <span class="class"><span class="keyword">class</span> <span class="title">COWIterator</span><<span class="title">E</span>> <span class="keyword">implements</span> <span class="title">ListIterator</span><<span class="title">E</span>> </span>{</span><br><span class="line"> <span class="comment">/** Snapshot of the array */</span></span><br><span class="line"> <span class="keyword">private</span> <span class="keyword">final</span> Object[] snapshot;</span><br><span class="line"> <span class="comment">/** Index of element to be returned by subsequent call to next. */</span></span><br><span class="line"> <span class="keyword">private</span> <span class="keyword">int</span> cursor;</span><br><span class="line"></span><br><span class="line"> <span class="function"><span class="keyword">private</span> <span class="title">COWIterator</span><span class="params">(Object[] elements, <span class="keyword">int</span> initialCursor)</span> </span>{</span><br><span class="line"> cursor = initialCursor;</span><br><span class="line"> snapshot = elements;</span><br><span class="line"> }</span><br><span class="line"></span><br><span class="line"> <span class="function"><span class="keyword">public</span> <span class="keyword">boolean</span> <span class="title">hasNext</span><span class="params">()</span> </span>{</span><br><span class="line"> <span class="keyword">return</span> cursor < snapshot.length;</span><br><span class="line"> }</span><br><span class="line"> ......</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p>可以看到，迭代器也是弱一致性的，并没有在锁中进行。如果其他线程没有对CopyOnWriteArrayList进行增删改的操作，那么snapshot还是创建迭代器时获取的array，但是如果其他线程对CopyOnWriteArrayList进行了增删改的操作，旧的数组会被新的数组给替换掉，但是snapshot还是原来旧的数组的引用：</p><figure class="highlight java"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">CopyOnWriteArrayList<String> list = <span class="keyword">new</span> CopyOnWriteArrayList<>();</span><br><span class="line">list.add(<span class="string">"hello"</span>);</span><br><span class="line">Iterator<String> iterator = list.iterator();</span><br><span class="line">list.add(<span class="string">"world"</span>);</span><br><span class="line"><span class="keyword">while</span> (iterator.hasNext()){</span><br><span class="line"> System.out.println(iterator.next());</span><br><span class="line">}</span><br></pre></td></tr></table></figure><p></p><p>输出结果仅为hello。</p><h3 id="总结"><a href="#总结" class="headerlink" title="总结"></a>总结</h3><ol><li>CopyOnWriteArrayList体现了写时复制的思想，增删改操作都是在复制的新数组中进行的；</li><li>CopyOnWriteArrayList的取值方法是弱一致性的，无法确保实时取到最新的数据；</li><li>CopyOnWriteArrayList的增删改方法通过可重入锁确保线程安全；</li><li>CopyOnWriteArrayList线程安全体现在多线程增删改不会抛出<code>java.util.ConcurrentModificationException</code>异常，并不能确保数据的强一致性；</li><li>同一时刻只能有一个线程对CopyOnWriteArrayList进行增删改操作，而读操作没有限制，并且 CopyOnWriteArrayList增删改操作都需要复制一份新数组，增加了内存消耗，所以CopyOnWriteArrayList适合读多写少的情况。</li></ol><script>$(".post-body a").not(".thispage").addClass("ignore-href").attr("target","_blank")</script></div><div></div><div><div style="padding:10px 0;margin:20px auto;width:90%;text-align:center;color:#878787" id="reward-div"><div>请作者喝瓶肥宅水🥤</div><button id="rewardButton" style="margin-top:10px" disable="enable" onclick='var e=document.getElementById("QR");"none"===e.style.display?e.style.display="block":e.style.display="none"'><span style="height:46px;width:46px;line-height:46px;border-radius:50%;color:#fe5f55;font-weight:600;background:#ffd5be;border:none;box-shadow:0 4px 8px 0 rgba(255,213,190,.4)">￥</span></button><div id="QR" style="display:none"><div id="wechat" style="display:inline-block"><img id="wechat_qr" src="/img/wechat_pay.png" alt="MrBird WeChat Pay"></div><div id="alipay" style="display:inline-block"><img id="alipay_qr" src="/img/ali_pay.png" alt="MrBird Alipay"></div></div></div><style>#QR img{width:auto;margin:.8em 1em 0 1em}</style></div><div><ul class="post-copyright"><li class="post-copyright-author"><strong>本文作者：</strong> MrBird</li><li class="post-copyright-link"><strong>本文链接：</strong> <a href="http://mrbird.cc/CopyOnWriteArrayList源码解析.html" title="CopyOnWriteArrayList源码解析">http://mrbird.cc/CopyOnWriteArrayList源码解析.html</a></li><li class="post-copyright-license"><strong>版权声明： </strong>本博客所有文章除特别声明外，均采用 <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" rel="external nofollow" target="_blank">CC BY-NC-SA 4.0</a> 许可协议。转载请注明出处！</li></ul></div><footer class="post-footer"><div class="post-tags" style="margin-bottom:1.3rem"><a href="/tags/Java/" rel="tag"># Java</a></div><div class="post-nav"><div class="post-nav-next post-nav-item"><a href="/Vector源码解析.html" rel="next" title="Vector源码解析"><i class="fa fa-chevron-left"></i> Vector源码解析</a></div><span class="post-nav-divider"></span><div class="post-nav-prev post-nav-item"><a href="/HashSet源码解析.html" rel="prev" title="HashSet源码解析">HashSet源码解析 <i class="fa fa-chevron-right"></i></a></div></div></footer></article><hr><div id="container"></div><div class="post-spread"><div id="comment-div"></div><style>.valine .vlist{margin-bottom:3rem}.valine .vwrap .vcontrol .col.col-60{text-align:left}.valine .vlist .vcard .vhead,.valine .vlist .vcard section .vfooter{text-align:left}.valine .vlist .vcard section{padding-bottom:.5rem!important}.vname{color:#6db33f!important}div#comment-div{margin-bottom:-8rem}.valine .vlist .vcard .vcontent .code,.valine .vlist .vcard .vcontent code,.valine .vlist .vcard .vcontent pre{background:#fbfbfb}.valine .vlist .vcard .vcontent a{color:#6db33f}.valine .vlist .vcard .vimg{border-radius:3px}.valine .vinfo{text-align:left}.valine .vbtn{border-radius:2px;padding:.3rem 1.25rem}.valine .vbtn:active,.valine .vbtn:hover{color:#6db33f;border-color:#6db33f;background-color:#fff}.valine .vwrap .vheader .vinput:focus{border-bottom-color:#6db33f}.valine .vlist .vcard .vcontent.expand:before{background:-webkit-gradient(linear,left top,left bottom,from(hsla(0,0%,100%,0)),to(hsla(0,0%,100%,.2)));background:linear-gradient(180deg,hsla(0,0%,100%,0),hsla(0,0%,100%,.2))}.valine .vlist .vcard .vcontent.expand:after{content:"点击展开";font-size:.4rem;text-align:right;left:-1rem;background:hsla(0,0%,100%,.2)}.valine .vlist .vcard section .vfooter .vat{color:#b3b3b3}.valine .vlist .vcard section .vfooter .vat:hover{color:#6db33f}.vcontent img{margin:0}.valine .info{display:none}</style><script type="text/javascript" src="/js/av.min.js"></script><script type="text/javascript" src="/js/Valine.min.js"></script><script type="text/javascript" src="/js/activate-power-mode.js"></script><script>POWERMODE.colorful=!0,POWERMODE.shake=!1,document.body.addEventListener("input",POWERMODE),new Valine({el:"#comment-div",notify:!1,verify:!0,appId:"SMcDFP1bN1jgb9Lo8JmtICHm-gzGzoHsz",appKey:"dH4nrUrt3V5XiJiI6Qyejnbi",placeholder:"",path:window.location.pathname,avatar:"monsterid",guest_info:["nick","mail","link"]});var chicken='<a href="#"><img src="https://image.uisdc.com/wp-content/uploads/2018/06/uisdc-chat-chicken.gif" class="checken"></a>';$("#comment-div").prepend(chicken)</script></div></div><script>var $bqinline=$("img[alt='bq-inline']");$bqinline.css({width:"2.3rem",height:"2.3rem",display:"inline","vertical-align":"text-bottom"})</script></div><div class="comments" id="comments"></div></div><aside id="sidebar" class="sidebar" onselectstart="return!1"><div class="sidebar-inner"><ul class="sidebar-nav motion-element"><li class="sidebar-nav-toc sidebar-nav-active" data-target="post-toc-wrap">Contents</li><li class="sidebar-nav-overview" data-target="site-overview">Site Preview</li></ul><section class="site-overview sidebar-panel"><div class="sidebar-sticky sticky"><div itemscope itemtype="https://mrbird.cc"><div class="author__header"><div class="author__avatar"><img src="/images/blogImage.jpg" class="author__avatar" alt="MrBird" itemprop="image"></div><div class="author__content"><div class="author__name" itemprop="name">MrBird</div><p class="author__bio" itemprop="description">A simple blog, code repository, just keep blogging</p></div><div class="author__count"><a href="/archives" class="ignore-href"><span class="count">14</span> <span>Archives</span> </a><a href="/tags" class="ignore-href"><span class="count">2</span> <span>Labels</span></a></div></div><div class="author__urls-wrapper"><ul class="author__urls social-icons"><li><a href="/" itemprop="url" class="ignore-href">🏠 Home</a></li><li><a href="/archives" itemprop="url" class="ignore-href">📦 Archives</a></li><li><a href="/tags" itemprop="url" class="ignore-href">🔖 Labels</a></li><li><a href="/friends" itemprop="url" class="ignore-href">👬 Friends</a></li><li><a href="javascript:;" class="popup-trigger animsition-link">🔍 Search</a></li></ul></div></div></div></section><section class="post-toc-wrap motion-element sidebar-panel sidebar-panel-active"><div class="post-toc"><div class="post-toc-content"><ol class="nav"><li class="nav-item nav-level-2"><a class="nav-link" href="#类结构"><span class="nav-number">1.</span> <span class="nav-text">类结构</span></a></li><li class="nav-item nav-level-2"><a class="nav-link" href="#方法解析"><span class="nav-number">2.</span> <span class="nav-text">方法解析</span></a><ol class="nav-child"><li class="nav-item nav-level-3"><a class="nav-link" href="#构造函数"><span class="nav-number">2.1.</span> <span class="nav-text">构造函数</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#add-E-e"><span class="nav-number">2.2.</span> <span class="nav-text">add(E e)</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#add-int-index-E-element"><span class="nav-number">2.3.</span> <span class="nav-text">add(int index, E element)</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#set-int-index-E-element"><span class="nav-number">2.4.</span> <span class="nav-text">set(int index, E element)</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#remove-int-index"><span class="nav-number">2.5.</span> <span class="nav-text">remove(int index)</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#get-int-index"><span class="nav-number">2.6.</span> <span class="nav-text">get(int index)</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#size"><span class="nav-number">2.7.</span> <span class="nav-text">size()</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#迭代器"><span class="nav-number">2.8.</span> <span class="nav-text">迭代器</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#总结"><span class="nav-number">2.9.</span> <span class="nav-text">总结</span></a></li></ol></li></ol></div></div></section></div><div id="asider-footer"><div id="links"><li><a href="https://love.mrbird.cc" target="_blank" itemprop="url" class="ignore-href"><i class="fa fa-fw fa-diamond" aria-hidden="true"></i></a></li><li><a href="https://cloud.mrbird.cn" target="_blank" itemprop="url" class="ignore-href"><i class="fa fa-fw fa-skyatlas" aria-hidden="true"></i></a></li><li><a href="https://gitee.com/mrbirdd" target="_blank" itemprop="sameAs" class="ignore-href"><i class="fa fa-fw fa-codepen" aria-hidden="true"></i></a></li><li><a href="https://github.com/wuyouzhuguli" target="_blank" itemprop="sameAs" class="ignore-href"><i class="fa fa-fw fa-github-alt" aria-hidden="true"></i></a></li></div><div id="author"></div><script type="text/javascript">var $smsheoschzd100dn="@ 2016 - "+(new Date).getFullYear()+" MrBird";document.getElementById("author").innerHTML=$smsheoschzd100dn</script><div><script type="text/javascript" src="/js/busuanzi.js"></script> UV <span class="busuanzi-value" id="busuanzi_value_site_uv" style="cursor:pointer" title="统计开始时间：2019年7月5日"></span> PV <span class="busuanzi-value" id="busuanzi_value_site_pv" style="cursor:pointer" title="统计开始时间：2019年7月5日"></span></div></div><script>function c__(){var o=sidebar_nav_toc.attr("class");o.indexOf("active")!=-1?footer.hide(300):footer.show(300)}var sidebar_nav_toc=$(".sidebar-nav-toc"),footer=$("#asider-footer");c__(),$(".sidebar-nav").on("click",function(){c__()})</script></aside></div></main><div class="back-to-top"><span id="scrollpercent"><span>0</span></span></div></div><script type="text/javascript">"[object Function]"!==Object.prototype.toString.call(window.Promise)&&(window.Promise=null)</script><script type="text/javascript" src="/lib/jquery/index.js?v=2.1.3"></script><script type="text/javascript" src="/lib/fastclick/lib/fastclick.min.js?v=1.0.6"></script><script type="text/javascript" src="/lib/jquery_lazyload/jquery.lazyload.js?v=1.9.7"></script><script type="text/javascript" src="/lib/velocity/velocity.min.js?v=1.2.1"></script><script type="text/javascript" src="/lib/velocity/velocity.ui.min.js?v=1.2.1"></script><script type="text/javascript" src="/js/src/utils.js?v=5.1.1"></script><script type="text/javascript" src="/js/src/motion.js?v=5.1.1"></script><script type="text/javascript" src="/js/src/scrollspy.js?v=5.1.1"></script><script type="text/javascript" src="/js/src/post-details.js?v=5.1.1"></script><script type="text/javascript" src="/js/src/bootstrap.js?v=5.1.1"></script><script type="text/javascript">function proceedsearch(){$("body").append('<div class="search-popup-overlay local-search-pop-overlay"></div>').css("overflow","hidden"),$(".search-popup-overlay").click(onPopupClose),$(".popup").toggle();var t=$("#local-search-input");t.attr("autocapitalize","none"),t.attr("autocorrect","off"),t.focus()}var isfetched=!1,isXml=!0,search_path="search.xml";0===search_path.length?search_path="search.xml":search_path.endsWith("json")&&(isXml=!1);var path="/"+search_path,onPopupClose=function(t){$(".popup").hide(),$("#local-search-input").val(""),$(".search-result-list").remove(),$("#no-result").remove(),$(".local-search-pop-overlay").remove(),$("body").css("overflow","")},searchFunc=function(t,e,o){"use strict";$("body").append('<div class="search-popup-overlay local-search-pop-overlay"><div id="search-loading-icon"><i class="fa fa-spinner fa-pulse fa-2x fa-fw"></i></div></div>').css("overflow","hidden"),$("#search-loading-icon").css("margin","20% auto 0 auto").css("text-align","center"),$.ajax({url:t,dataType:isXml?"xml":"json",async:!0,success:function(t){isfetched=!0,$(".popup").detach().appendTo(".header-inner");var n=isXml?$("entry",t).map(function(){return{title:$("title",this).text(),content:$("content",this).text(),url:$("url",this).text()}}).get():t,r=document.getElementById(e),s=document.getElementById(o),a=function(){var t=r.value.trim().toLowerCase(),e=t.split(/[\s\-]+/);e.length>1&&e.push(t);var o=[];if(t.length>0&&n.forEach(function(n){function r(e,o,n,r){for(var s=r[r.length-1],a=s.position,i=s.word,l=[],h=0;a+i.length<=n&&0!=r.length;){i===t&&h++,l.push({position:a,length:i.length});var p=a+i.length;for(r.pop();0!=r.length&&(s=r[r.length-1],a=s.position,i=s.word,p>a);)r.pop()}return c+=h,{hits:l,start:o,end:n,searchTextCount:h}}function s(t,e){var o="",n=e.start;return e.hits.forEach(function(e){o+=t.substring(n,e.position);var r=e.position+e.length;o+='<b class="search-keyword">'+t.substring(e.position,r)+"</b>",n=r}),o+=t.substring(n,e.end)}var a=!1,i=0,c=0,l=n.title.trim(),h=l.toLowerCase(),p=n.content.trim().replace(/<[^>]+>/g,""),u=p.toLowerCase(),f=decodeURIComponent(n.url),d=[],g=[];if(""!=l&&(e.forEach(function(t){function e(t,e,o){var n=t.length;if(0===n)return[];var r=0,s=[],a=[];for(o||(e=e.toLowerCase(),t=t.toLowerCase());(s=e.indexOf(t,r))>-1;)a.push({position:s,word:t}),r=s+n;return a}d=d.concat(e(t,h,!1)),g=g.concat(e(t,u,!1))}),(d.length>0||g.length>0)&&(a=!0,i=d.length+g.length)),a){[d,g].forEach(function(t){t.sort(function(t,e){return e.position!==t.position?e.position-t.position:t.word.length-e.word.length})});var v=[];0!=d.length&&v.push(r(l,0,l.length,d));for(var C=[];0!=g.length;){var $=g[g.length-1],m=$.position,x=$.word,w=m-20,y=m+80;w<0&&(w=0),y<m+x.length&&(y=m+x.length),y>p.length&&(y=p.length),C.push(r(p,w,y,g))}C.sort(function(t,e){return t.searchTextCount!==e.searchTextCount?e.searchTextCount-t.searchTextCount:t.hits.length!==e.hits.length?e.hits.length-t.hits.length:t.start-e.start});var T=parseInt("1");T>=0&&(C=C.slice(0,T));var b="";b+=0!=v.length?"<li><a href='"+f+"' class='search-result-title'>"+s(l,v[0])+"</a>":"<li><a href='"+f+"' class='search-result-title'>"+l+"</a>",C.forEach(function(t){b+="<a href='"+f+'\'><p class="search-result">'+s(p,t)+"...</p></a>"}),b+="</li>",o.push({item:b,searchTextCount:c,hitCount:i,id:o.length})}}),1===e.length&&""===e[0])s.innerHTML='<div id="no-result"><i class="fa fa-search fa-5x" /></div>';else if(0===o.length)s.innerHTML='<div id="no-result"><i class="fa fa-frown-o fa-5x" /></div>';else{o.sort(function(t,e){return t.searchTextCount!==e.searchTextCount?e.searchTextCount-t.searchTextCount:t.hitCount!==e.hitCount?e.hitCount-t.hitCount:e.id-t.id});var a='<ul class="search-result-list">';o.forEach(function(t){a+=t.item}),a+="</ul>",s.innerHTML=a}};r.addEventListener("input",a),$(".local-search-pop-overlay").remove(),$("body").css("overflow",""),proceedsearch()}})};$(".popup-trigger").click(function(t){t.stopPropagation(),isfetched===!1?searchFunc(path,"local-search-input","local-search-result"):proceedsearch()}),$(".popup-btn-close").click(onPopupClose),$(".popup").click(function(t){t.stopPropagation()}),$(document).on("keyup",function(t){var e=27===t.which&&$(".search-popup").is(":visible");e&&onPopupClose()})</script></body><script>$(function(){$("a").not(".nav-link,.cloud-tie-join-count,.ignore-href,.jstree-anchor").addClass("animsition-link")});var burst1=new mojs.Burst({left:0,top:0,radius:{5:40},children:{shape:"circle",fill:["red","cyan","orange"],fillOpacity:.8,radiusX:3.5,radiusY:3.5}});document.addEventListener("click",function(a){null==a.target.href&&"footer"!=a.target.className&&"copyright"!=a.target.className&&"author__urls social-icons"!=a.target.className&&"author__avatar"!=a.target.className&&"sidebar sidebar-active"!=a.target.className&&burst1.tune({x:a.pageX,y:a.pageY}).generate().replay()})</script><script type="text/javascript" src="/js/message.js"></script></html><!-- rebuild by neat -->