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<!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>AdaptiveRevisitQueueList xref</title><link type="text/css" rel="stylesheet" href="../../../../stylesheet.css" /></head><body><div id="overview"><a href="../../../../../apidocs/org/archive/crawler/frontier/AdaptiveRevisitQueueList.html">View Javadoc</a></div><pre><a name="1" href="#1">1</a> <em class="comment">/*<em class="comment"> ARHostQueueList.java</em></em><a name="2" href="#2">2</a> <em class="comment">*</em><a name="3" href="#3">3</a> <em class="comment">* Created on Sep 13, 2004</em><a name="4" href="#4">4</a> <em class="comment">*</em><a name="5" href="#5">5</a> <em class="comment">* Copyright (C) 2004 Kristinn Sigur?sson.</em><a name="6" href="#6">6</a> <em class="comment">*</em><a name="7" href="#7">7</a> <em class="comment">* This file is part of the Heritrix web crawler (crawler.archive.org).</em><a name="8" href="#8">8</a> <em class="comment">*</em><a name="9" href="#9">9</a> <em class="comment">* Heritrix is free software; you can redistribute it and/or modify</em><a name="10" href="#10">10</a> <em class="comment">* it under the terms of the GNU Lesser Public License as published by</em><a name="11" href="#11">11</a> <em class="comment">* the Free Software Foundation; either version 2.1 of the License, or</em><a name="12" href="#12">12</a> <em class="comment">* any later version.</em><a name="13" href="#13">13</a> <em class="comment">*</em><a name="14" href="#14">14</a> <em class="comment">* Heritrix is distributed in the hope that it will be useful,</em><a name="15" href="#15">15</a> <em class="comment">* but WITHOUT ANY WARRANTY; without even the implied warranty of</em><a name="16" href="#16">16</a> <em class="comment">* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</em><a name="17" href="#17">17</a> <em class="comment">* GNU Lesser Public License for more details.</em><a name="18" href="#18">18</a> <em class="comment">*</em><a name="19" href="#19">19</a> <em class="comment">* You should have received a copy of the GNU Lesser Public License</em><a name="20" href="#20">20</a> <em class="comment">* along with Heritrix; if not, write to the Free Software</em><a name="21" href="#21">21</a> <em class="comment">* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</em><a name="22" href="#22">22</a> <em class="comment">*/</em><a name="23" href="#23">23</a> <strong>package</strong> <a href="../../../../org/archive/crawler/frontier/package-summary.html">org.archive.crawler.frontier</a>;<a name="24" href="#24">24</a> <a name="25" href="#25">25</a> <strong>import</strong> java.io.IOException;<a name="26" href="#26">26</a> <strong>import</strong> java.io.PrintWriter;<a name="27" href="#27">27</a> <strong>import</strong> java.util.HashMap;<a name="28" href="#28">28</a> <strong>import</strong> java.util.Iterator;<a name="29" href="#29">29</a> <strong>import</strong> java.util.TreeSet;<a name="30" href="#30">30</a> <strong>import</strong> java.util.logging.Level;<a name="31" href="#31">31</a> <strong>import</strong> java.util.logging.Logger;<a name="32" href="#32">32</a> <a name="33" href="#33">33</a> <strong>import</strong> org.archive.util.ArchiveUtils;<a name="34" href="#34">34</a> <strong>import</strong> org.archive.util.Reporter;<a name="35" href="#35">35</a> <a name="36" href="#36">36</a> <strong>import</strong> com.sleepycat.bind.EntryBinding;<a name="37" href="#37">37</a> <strong>import</strong> com.sleepycat.bind.serial.StoredClassCatalog;<a name="38" href="#38">38</a> <strong>import</strong> com.sleepycat.bind.tuple.IntegerBinding;<a name="39" href="#39">39</a> <strong>import</strong> com.sleepycat.bind.tuple.StringBinding;<a name="40" href="#40">40</a> <strong>import</strong> com.sleepycat.je.Cursor;<a name="41" href="#41">41</a> <strong>import</strong> com.sleepycat.je.Database;<a name="42" href="#42">42</a> <strong>import</strong> com.sleepycat.je.DatabaseConfig;<a name="43" href="#43">43</a> <strong>import</strong> com.sleepycat.je.DatabaseEntry;<a name="44" href="#44">44</a> <strong>import</strong> com.sleepycat.je.DatabaseException;<a name="45" href="#45">45</a> <strong>import</strong> com.sleepycat.je.Environment;<a name="46" href="#46">46</a> <strong>import</strong> com.sleepycat.je.LockMode;<a name="47" href="#47">47</a> <strong>import</strong> com.sleepycat.je.OperationStatus;<a name="48" href="#48">48</a> <a name="49" href="#49">49</a> <em>/**<em>*</em></em><a name="50" href="#50">50</a> <em> * Maintains an ordered list of {@link AdaptiveRevisitHostQueue}s used by a</em><a name="51" href="#51">51</a> <em> * Frontier.</em><a name="52" href="#52">52</a> <em> * <p> </em><a name="53" href="#53">53</a> <em> * The list is ordered by the </em><a name="54" href="#54">54</a> <em> * {@link AdaptiveRevisitHostQueue#getNextReadyTime() AdaptiveRevisitHostQueue.getNextReadyTime()}, </em><a name="55" href="#55">55</a> <em> * smallest value at the top of the list and then on in descending order.</em><a name="56" href="#56">56</a> <em> * <p></em><a name="57" href="#57">57</a> <em> * The list will maintain a list of hostnames in a seperate DB. On creation a</em><a name="58" href="#58">58</a> <em> * list will try to open the DB at a specified location. If it already exists</em><a name="59" href="#59">59</a> <em> * the list will create HQs for all the hostnames in the list, discarding </em><a name="60" href="#60">60</a> <em> * those that turn out to be empty.</em><a name="61" href="#61">61</a> <em> * <p></em><a name="62" href="#62">62</a> <em> * Any BDB DatabaseException will be converted to an IOException by public </em><a name="63" href="#63">63</a> <em> * methods. This includes preserving the original stacktrace, in favor of the</em><a name="64" href="#64">64</a> <em> * one created for the IOException, so that the true source of the exception</em><a name="65" href="#65">65</a> <em> * is not lost. </em><a name="66" href="#66">66</a> <em> *</em><a name="67" href="#67">67</a> <em> * @author Kristinn Sigurdsson</em><a name="68" href="#68">68</a> <em> */</em><a name="69" href="#69">69</a> <strong>public</strong> <strong>class</strong> <a href="../../../../org/archive/crawler/frontier/AdaptiveRevisitQueueList.html">AdaptiveRevisitQueueList</a> implements <a href="../../../../org/archive/util/Reporter.html">Reporter</a> {<a name="70" href="#70">70</a> <a name="71" href="#71">71</a> <em class="comment">// TODO: Handle HQs becoming empty.</em><a name="72" href="#72">72</a> <a name="73" href="#73">73</a> <em>/**<em>* The Environment for the BerkleyDB databases in the HQs */</em></em><a name="74" href="#74">74</a> <strong>private</strong> <strong>final</strong> Environment env;<a name="75" href="#75">75</a> <strong>private</strong> <strong>final</strong> StoredClassCatalog catalog;<a name="76" href="#76">76</a> <em>/**<em>* Contains host names for all HQs. Name is key, valence is value */</em></em><a name="77" href="#77">77</a> <strong>private</strong> Database hostNamesDB;<a name="78" href="#78">78</a> <strong>private</strong> EntryBinding keyBinding;<a name="79" href="#79">79</a> <strong>private</strong> EntryBinding valueBinding;<a name="80" href="#80">80</a> <a name="81" href="#81">81</a> <em>/**<em>* A hash table of all the HQs (wrapped), keyed by hostName */</em></em><a name="82" href="#82">82</a> <strong>private</strong> HashMap<String,AdaptiveRevisitHostQueueWrapper> hostQueues; <a name="83" href="#83">83</a> <em>/**<em>* Contains the hostQueues (wrapped) sorted by their time of next fetch */</em></em><a name="84" href="#84">84</a> <strong>private</strong> TreeSet<AdaptiveRevisitHostQueueWrapper> sortedHostQueues;<a name="85" href="#85">85</a> <em>/**<em>* Logger */</em></em><a name="86" href="#86">86</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> Logger logger =<a name="87" href="#87">87</a> Logger.getLogger(AdaptiveRevisitQueueList.<strong>class</strong>.getName());<a name="88" href="#88">88</a> <a name="89" href="#89">89</a> <a name="90" href="#90">90</a> <strong>public</strong> <a href="../../../../org/archive/crawler/frontier/AdaptiveRevisitQueueList.html">AdaptiveRevisitQueueList</a>(Environment env,<a name="91" href="#91">91</a> StoredClassCatalog catalog)<a name="92" href="#92">92</a> throws IOException {<a name="93" href="#93">93</a> Cursor cursor = <strong>null</strong>;<a name="94" href="#94">94</a> <strong>try</strong> {<a name="95" href="#95">95</a> <strong>this</strong>.env = env;<a name="96" href="#96">96</a> <strong>this</strong>.catalog = catalog;<a name="97" href="#97">97</a> keyBinding = <strong>new</strong> StringBinding();<a name="98" href="#98">98</a> valueBinding = <strong>new</strong> IntegerBinding();<a name="99" href="#99">99</a> <a name="100" href="#100">100</a> <em class="comment">// Then initialize other data</em><a name="101" href="#101">101</a> hostQueues = <strong>new</strong> HashMap<String,AdaptiveRevisitHostQueueWrapper>();<a name="102" href="#102">102</a> sortedHostQueues = <strong>new</strong> TreeSet<AdaptiveRevisitHostQueueWrapper>();<a name="103" href="#103">103</a> <a name="104" href="#104">104</a> <em class="comment">// Open the hostNamesDB</em><a name="105" href="#105">105</a> DatabaseConfig dbConfig = <strong>new</strong> DatabaseConfig();<a name="106" href="#106">106</a> dbConfig.setTransactional(false);<a name="107" href="#107">107</a> dbConfig.setAllowCreate(<strong>true</strong>);<a name="108" href="#108">108</a> hostNamesDB = env.openDatabase(<strong>null</strong>, <span class="string">"hostNames"</span>, dbConfig);<a name="109" href="#109">109</a> <a name="110" href="#110">110</a> <em class="comment">// Read any existing hostNames and create relevant HQs</em><a name="111" href="#111">111</a> cursor = hostNamesDB.openCursor(<strong>null</strong>, <strong>null</strong>);<a name="112" href="#112">112</a> DatabaseEntry keyEntry = <strong>new</strong> DatabaseEntry();<a name="113" href="#113">113</a> DatabaseEntry dataEntry = <strong>new</strong> DatabaseEntry();<a name="114" href="#114">114</a> OperationStatus opStatus = cursor.getFirst(keyEntry, dataEntry,<a name="115" href="#115">115</a> LockMode.DEFAULT);<a name="116" href="#116">116</a> <strong>while</strong> (opStatus == OperationStatus.SUCCESS) {<a name="117" href="#117">117</a> <em class="comment">// Got one!</em><a name="118" href="#118">118</a> String hostName = (String)keyBinding.entryToObject(keyEntry);<a name="119" href="#119">119</a> <strong>int</strong> valence = ((Integer)valueBinding.entryToObject(dataEntry)).<a name="120" href="#120">120</a> intValue();<a name="121" href="#121">121</a> opStatus = cursor.getNext(keyEntry, dataEntry, LockMode.DEFAULT);<a name="122" href="#122">122</a> <em class="comment">// Create HQ</em><a name="123" href="#123">123</a> createHQ(hostName, valence);<a name="124" href="#124">124</a> <em class="comment">// TODO: If the hq is empty, then it can be discarded</em><a name="125" href="#125">125</a> <em class="comment">// immediately</em><a name="126" href="#126">126</a> }<a name="127" href="#127">127</a> } <strong>catch</strong> (DatabaseException e) {<a name="128" href="#128">128</a> <strong>throw</strong> convertDbException(e);<a name="129" href="#129">129</a> } <strong>finally</strong> {<a name="130" href="#130">130</a> <strong>if</strong> (cursor != <strong>null</strong>) {<a name="131" href="#131">131</a> <strong>try</strong> {<a name="132" href="#132">132</a> cursor.close();<a name="133" href="#133">133</a> } <strong>catch</strong> (DatabaseException e) {<a name="134" href="#134">134</a> <strong>throw</strong> convertDbException(e);<a name="135" href="#135">135</a> }<a name="136" href="#136">136</a> }<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> <strong>private</strong> IOException convertDbException(Exception e) {<a name="141" href="#141">141</a> IOException e2 = <strong>new</strong> IOException(e.getMessage());<a name="142" href="#142">142</a> e2.setStackTrace(e.getStackTrace());<a name="143" href="#143">143</a> <strong>return</strong> e2;<a name="144" href="#144">144</a> }<a name="145" href="#145">145</a> <a name="146" href="#146">146</a> <em>/**<em>*</em></em><a name="147" href="#147">147</a> <em> * Get an AdaptiveRevisitHostQueue for the specified host.</em><a name="148" href="#148">148</a> <em> * <p></em><a name="149" href="#149">149</a> <em> * If one does not already exist, null is returned </em><a name="150" href="#150">150</a> <em> * </em>?? 快捷鍵說明
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