📄 objectplusfilesoutputstream.html
字号:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><head><meta http-equiv="content-type" content="text/html; charset=UTF-8" /><title>ObjectPlusFilesOutputStream xref</title><link type="text/css" rel="stylesheet" href="../../../stylesheet.css" /></head><body><div id="overview"><a href="../../../../apidocs/org/archive/io/ObjectPlusFilesOutputStream.html">View Javadoc</a></div><pre><a name="1" href="#1">1</a> <em class="comment">/*<em class="comment"> ObjectPlusFilesOutputStream</em></em><a name="2" href="#2">2</a> <em class="comment">*</em><a name="3" href="#3">3</a> <em class="comment">* $Id: ObjectPlusFilesOutputStream.java,v 1.2 2005/11/02 23:36:13 stack-sf Exp $</em><a name="4" href="#4">4</a> <em class="comment">*</em><a name="5" href="#5">5</a> <em class="comment">* Created on Apr 28, 2004</em><a name="6" href="#6">6</a> <em class="comment">*</em><a name="7" href="#7">7</a> <em class="comment">* Copyright (C) 2004 Internet Archive.</em><a name="8" href="#8">8</a> <em class="comment">*</em><a name="9" href="#9">9</a> <em class="comment">* This file is part of the Heritrix web crawler (crawler.archive.org).</em><a name="10" href="#10">10</a> <em class="comment">*</em><a name="11" href="#11">11</a> <em class="comment">* Heritrix is free software; you can redistribute it and/or modify</em><a name="12" href="#12">12</a> <em class="comment">* it under the terms of the GNU Lesser Public License as published by</em><a name="13" href="#13">13</a> <em class="comment">* the Free Software Foundation; either version 2.1 of the License, or</em><a name="14" href="#14">14</a> <em class="comment">* any later version.</em><a name="15" href="#15">15</a> <em class="comment">*</em><a name="16" href="#16">16</a> <em class="comment">* Heritrix is distributed in the hope that it will be useful,</em><a name="17" href="#17">17</a> <em class="comment">* but WITHOUT ANY WARRANTY; without even the implied warranty of</em><a name="18" href="#18">18</a> <em class="comment">* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</em><a name="19" href="#19">19</a> <em class="comment">* GNU Lesser Public License for more details.</em><a name="20" href="#20">20</a> <em class="comment">*</em><a name="21" href="#21">21</a> <em class="comment">* You should have received a copy of the GNU Lesser Public License</em><a name="22" href="#22">22</a> <em class="comment">* along with Heritrix; if not, write to the Free Software</em><a name="23" href="#23">23</a> <em class="comment">* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</em><a name="24" href="#24">24</a> <em class="comment">*/</em><a name="25" href="#25">25</a> <strong>package</strong> <a href="../../../org/archive/io/package-summary.html">org.archive.io</a>;<a name="26" href="#26">26</a> <a name="27" href="#27">27</a> <strong>import</strong> java.io.File;<a name="28" href="#28">28</a> <strong>import</strong> java.io.IOException;<a name="29" href="#29">29</a> <strong>import</strong> java.io.ObjectOutputStream;<a name="30" href="#30">30</a> <strong>import</strong> java.io.OutputStream;<a name="31" href="#31">31</a> <strong>import</strong> java.util.LinkedList;<a name="32" href="#32">32</a> <a name="33" href="#33">33</a> <strong>import</strong> org.archive.util.FileUtils;<a name="34" href="#34">34</a> <a name="35" href="#35">35</a> <a name="36" href="#36">36</a> <em>/**<em>*</em></em><a name="37" href="#37">37</a> <em> * Enhanced ObjectOutputStream which maintains (a stack of) auxiliary</em><a name="38" href="#38">38</a> <em> * directories and offers convenience methods for serialized objects</em><a name="39" href="#39">39</a> <em> * to save their related disk files alongside their serialized version.</em><a name="40" href="#40">40</a> <em> *</em><a name="41" href="#41">41</a> <em> * @author gojomo</em><a name="42" href="#42">42</a> <em> */</em><a name="43" href="#43">43</a> <strong>public</strong> <strong>class</strong> <a href="../../../org/archive/io/ObjectPlusFilesOutputStream.html">ObjectPlusFilesOutputStream</a> <strong>extends</strong> ObjectOutputStream {<a name="44" href="#44">44</a> LinkedList auxiliaryDirectoryStack = <strong>new</strong> LinkedList();<a name="45" href="#45">45</a> <a name="46" href="#46">46</a> <em>/**<em>*</em></em><a name="47" href="#47">47</a> <em> * Constructor</em><a name="48" href="#48">48</a> <em> *</em><a name="49" href="#49">49</a> <em> * @param out</em><a name="50" href="#50">50</a> <em> * @param topDirectory</em><a name="51" href="#51">51</a> <em> * @throws java.io.IOException</em><a name="52" href="#52">52</a> <em> */</em><a name="53" href="#53">53</a> <strong>public</strong> <a href="../../../org/archive/io/ObjectPlusFilesOutputStream.html">ObjectPlusFilesOutputStream</a>(OutputStream out, File topDirectory) throws IOException {<a name="54" href="#54">54</a> <strong>super</strong>(out);<a name="55" href="#55">55</a> auxiliaryDirectoryStack.addFirst(topDirectory);<a name="56" href="#56">56</a> }<a name="57" href="#57">57</a> <a name="58" href="#58">58</a> <em>/**<em>*</em></em><a name="59" href="#59">59</a> <em> * Add another subdirectory for any file-capture needs during the</em><a name="60" href="#60">60</a> <em> * current serialization.</em><a name="61" href="#61">61</a> <em> *</em><a name="62" href="#62">62</a> <em> * @param dir</em><a name="63" href="#63">63</a> <em> */</em><a name="64" href="#64">64</a> <strong>public</strong> <strong>void</strong> pushAuxiliaryDirectory(String dir) {<a name="65" href="#65">65</a> auxiliaryDirectoryStack.addFirst(<strong>new</strong> File(getAuxiliaryDirectory(),dir));<a name="66" href="#66">66</a> }<a name="67" href="#67">67</a> <a name="68" href="#68">68</a> <em>/**<em>*</em></em><a name="69" href="#69">69</a> <em> * Remove the top subdirectory.</em><a name="70" href="#70">70</a> <em> *</em><a name="71" href="#71">71</a> <em> */</em><a name="72" href="#72">72</a> <strong>public</strong> <strong>void</strong> popAuxiliaryDirectory() {<a name="73" href="#73">73</a> auxiliaryDirectoryStack.removeFirst();<a name="74" href="#74">74</a> }<a name="75" href="#75">75</a> <a name="76" href="#76">76</a> <em>/**<em>*</em></em><a name="77" href="#77">77</a> <em> * Return the current auxiliary directory for storing</em><a name="78" href="#78">78</a> <em> * files associated with serialized objects.</em><a name="79" href="#79">79</a> <em> *</em><a name="80" href="#80">80</a> <em> * @return Auxillary directory.</em><a name="81" href="#81">81</a> <em> */</em><a name="82" href="#82">82</a> <strong>public</strong> File getAuxiliaryDirectory() {<a name="83" href="#83">83</a> <strong>return</strong> (File)auxiliaryDirectoryStack.getFirst();<a name="84" href="#84">84</a> }<a name="85" href="#85">85</a> <a name="86" href="#86">86</a> <em>/**<em>*</em></em><a name="87" href="#87">87</a> <em> * Store a snapshot of an object's supporting file to the</em><a name="88" href="#88">88</a> <em> * current auxiliary directory. Should only be used for</em><a name="89" href="#89">89</a> <em> * files which are strictly appended-to, because it tries</em><a name="90" href="#90">90</a> <em> * to use a "hard link" where possible (meaning that</em><a name="91" href="#91">91</a> <em> * future edits to the original file's contents will</em><a name="92" href="#92">92</a> <em> * also affect the snapshot).</em><a name="93" href="#93">93</a> <em> *</em><a name="94" href="#94">94</a> <em> * Remembers current file extent to allow a future restore</em><a name="95" href="#95">95</a> <em> * to ignore subsequent appended data.</em><a name="96" href="#96">96</a> <em> *</em><a name="97" href="#97">97</a> <em> * @param file</em><a name="98" href="#98">98</a> <em> * @throws IOException</em><a name="99" href="#99">99</a> <em> */</em><a name="100" href="#100">100</a> <strong>public</strong> <strong>void</strong> snapshotAppendOnlyFile(File file) throws IOException {<a name="101" href="#101">101</a> <em class="comment">// write filename</em><a name="102" href="#102">102</a> String name = file.getName();<a name="103" href="#103">103</a> writeUTF(name);<a name="104" href="#104">104</a> <em class="comment">// write current file length</em><a name="105" href="#105">105</a> writeLong(file.length());<a name="106" href="#106">106</a> File auxDir = getAuxiliaryDirectory();<a name="107" href="#107">107</a> <strong>if</strong>(!auxDir.exists()) {<a name="108" href="#108">108</a> auxDir.mkdirs();<a name="109" href="#109">109</a> }<a name="110" href="#110">110</a> File destination = <strong>new</strong> File(auxDir,name);<a name="111" href="#111">111</a> hardlinkOrCopy(file, destination);<a name="112" href="#112">112</a> }<a name="113" href="#113">113</a> <a name="114" href="#114">114</a> <em>/**<em>*</em></em><a name="115" href="#115">115</a> <em> * Create a backup of this given file, first by trying a "hard</em><a name="116" href="#116">116</a> <em> * link", then by using a copy if hard linking is unavailable</em><a name="117" href="#117">117</a> <em> * (either because it is unsupported or the origin and checkpoint</em><a name="118" href="#118">118</a> <em> * directories are on different volumes).</em><a name="119" href="#119">119</a> <em> *</em><a name="120" href="#120">120</a> <em> * @param file</em><a name="121" href="#121">121</a> <em> * @param destination</em><a name="122" href="#122">122</a> <em> * @throws IOException</em><a name="123" href="#123">123</a> <em> */</em><a name="124" href="#124">124</a> <strong>private</strong> <strong>void</strong> hardlinkOrCopy(File file, File destination) throws IOException {<a name="125" href="#125">125</a> <em class="comment">// For Linux/UNIX, try a hard link first.</em><a name="126" href="#126">126</a> Process link = Runtime.getRuntime().exec(<span class="string">"ln "</span>+file.getAbsolutePath()+<span class="string">" "</span>+destination.getAbsolutePath());<a name="127" href="#127">127</a> <em class="comment">// TODO NTFS also supports hard links; add appropriate try</em><a name="128" href="#128">128</a> <strong>try</strong> {<a name="129" href="#129">129</a> link.waitFor();<a name="130" href="#130">130</a> } <strong>catch</strong> (InterruptedException e) {<a name="131" href="#131">131</a> <em class="comment">// TODO Auto-generated catch block</em><a name="132" href="#132">132</a> e.printStackTrace();<a name="133" href="#133">133</a> }<a name="134" href="#134">134</a> <strong>if</strong>(link.exitValue()!=0) {<a name="135" href="#135">135</a> <em class="comment">// hard link failed</em><a name="136" href="#136">136</a> FileUtils.copyFile(file,destination);<a name="137" href="#137">137</a> }<a name="138" href="#138">138</a> }<a name="139" href="#139">139</a> <a name="140" href="#140">140</a> }</pre><hr/><div id="footer">This page was automatically generated by <a href="http://maven.apache.org/">Maven</a></div></body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -