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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>WaitEvaluator xref</title><link type="text/css" rel="stylesheet" href="../../../../stylesheet.css" /></head><body><div id="overview"><a href="../../../../../apidocs/org/archive/crawler/postprocessor/WaitEvaluator.html">View Javadoc</a></div><pre><a name="1" href="#1">1</a> <em class="comment">/*<em class="comment"> WaitEvaluator</em></em><a name="2" href="#2">2</a> <em class="comment"> * </em><a name="3" href="#3">3</a> <em class="comment"> * $Id: WaitEvaluator.java,v 1.5 2005/04/05 20:27:17 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 26.11.2004</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/crawler/postprocessor/package-summary.html">org.archive.crawler.postprocessor</a>;<a name="26" href="#26">26</a> <a name="27" href="#27">27</a> <strong>import</strong> java.util.logging.Level;<a name="28" href="#28">28</a> <strong>import</strong> java.util.logging.Logger;<a name="29" href="#29">29</a> <a name="30" href="#30">30</a> <strong>import</strong> javax.management.AttributeNotFoundException;<a name="31" href="#31">31</a> <a name="32" href="#32">32</a> <strong>import</strong> org.archive.crawler.datamodel.CrawlURI;<a name="33" href="#33">33</a> <strong>import</strong> org.archive.crawler.framework.Processor;<a name="34" href="#34">34</a> <strong>import</strong> org.archive.crawler.frontier.AdaptiveRevisitAttributeConstants;<a name="35" href="#35">35</a> <strong>import</strong> org.archive.crawler.settings.SimpleType;<a name="36" href="#36">36</a> <a name="37" href="#37">37</a> <em>/**<em>*</em></em><a name="38" href="#38">38</a> <em> * A processor that determines when a URI should be revisited next. Does</em><a name="39" href="#39">39</a> <em> * <b>not</b> account for DNS and robots.txt expiration. That should be </em><a name="40" href="#40">40</a> <em> * handled seperately by the Frontiers.</em><a name="41" href="#41">41</a> <em> *</em><a name="42" href="#42">42</a> <em> * @author Kristinn Sigurdsson</em><a name="43" href="#43">43</a> <em> */</em><a name="44" href="#44">44</a> <strong>public</strong> <strong>class</strong> <a href="../../../../org/archive/crawler/postprocessor/WaitEvaluator.html">WaitEvaluator</a> <strong>extends</strong> <a href="../../../../org/archive/crawler/framework/Processor.html">Processor</a><a name="45" href="#45">45</a> implements <a href="../../../../org/archive/crawler/frontier/AdaptiveRevisitAttributeConstants.html">AdaptiveRevisitAttributeConstants</a> {<a name="46" href="#46">46</a> <a name="47" href="#47">47</a> Logger logger = Logger.getLogger(WaitEvaluator.<strong>class</strong>.getName());<a name="48" href="#48">48</a> <a name="49" href="#49">49</a> <em>/**<em>* Default wait time after initial visit. */</em></em><a name="50" href="#50">50</a> <strong>public</strong> <strong>final</strong> <strong>static</strong> String ATTR_INITIAL_WAIT_INTERVAL =<a name="51" href="#51">51</a> <span class="string">"initial-wait-interval-seconds"</span>;<a name="52" href="#52">52</a> <strong>protected</strong> <strong>final</strong> <strong>static</strong> Long DEFAULT_INITIAL_WAIT_INTERVAL =<a name="53" href="#53">53</a> <strong>new</strong> Long(86400); <em class="comment">// 1 day</em><a name="54" href="#54">54</a> <em>/**<em>* Maximum wait between visits */</em></em><a name="55" href="#55">55</a> <strong>public</strong> <strong>final</strong> <strong>static</strong> String ATTR_MAX_WAIT_INTERVAL =<a name="56" href="#56">56</a> <span class="string">"max-wait-interval-seconds"</span>;<a name="57" href="#57">57</a> <strong>protected</strong> <strong>final</strong> <strong>static</strong> Long DEFAULT_MAX_WAIT_INTERVAL =<a name="58" href="#58">58</a> <strong>new</strong> Long(2419200); <em class="comment">// 4 weeks</em><a name="59" href="#59">59</a> <em>/**<em>* Minimum wait between visits */</em></em><a name="60" href="#60">60</a> <strong>public</strong> <strong>final</strong> <strong>static</strong> String ATTR_MIN_WAIT_INTERVAL =<a name="61" href="#61">61</a> <span class="string">"min-wait-interval-seconds"</span>;<a name="62" href="#62">62</a> <strong>protected</strong> <strong>final</strong> <strong>static</strong> Long DEFAULT_MIN_WAIT_INTERVAL =<a name="63" href="#63">63</a> <strong>new</strong> Long(3600); <em class="comment">// 1 hour</em><a name="64" href="#64">64</a> <em>/**<em>* Factor increase on wait when unchanged */</em></em><a name="65" href="#65">65</a> <strong>public</strong> <strong>final</strong> <strong>static</strong> String ATTR_UNCHANGED_FACTOR = <span class="string">"unchanged-factor"</span>;<a name="66" href="#66">66</a> <strong>protected</strong> <strong>final</strong> <strong>static</strong> Double DEFAULT_UNCHANGED_FACTOR = <strong>new</strong> Double(1.5); <a name="67" href="#67">67</a> <em>/**<em>* Factor decrease on wait when changed */</em></em><a name="68" href="#68">68</a> <strong>public</strong> <strong>final</strong> <strong>static</strong> String ATTR_CHANGED_FACTOR = <span class="string">"changed-factor"</span>;<a name="69" href="#69">69</a> <strong>protected</strong> <strong>final</strong> <strong>static</strong> Double DEFAULT_CHANGED_FACTOR = <strong>new</strong> Double(1.5); <a name="70" href="#70">70</a> <em>/**<em>* Fixed wait time for 'unknown' change status. I.e. wait time for URIs </em></em><a name="71" href="#71">71</a> <em> * whose content change detection is not available. */</em><a name="72" href="#72">72</a> <strong>public</strong> <strong>final</strong> <strong>static</strong> String ATTR_DEFAULT_WAIT_INTERVAL =<a name="73" href="#73">73</a> <span class="string">"default-wait-interval-seconds"</span>;<a name="74" href="#74">74</a> <strong>protected</strong> <strong>final</strong> <strong>static</strong> Long DEFAULT_DEFAULT_WAIT_INTERVAL =<a name="75" href="#75">75</a> <strong>new</strong> Long(259200); <em class="comment">// 3 days</em><a name="76" href="#76">76</a> <em>/**<em>* Indicates if the amount of time the URI was overdue should be added</em></em><a name="77" href="#77">77</a> <em> * to the wait time before the new wait time is calculated. */</em><a name="78" href="#78">78</a> <strong>public</strong> <strong>final</strong> <strong>static</strong> String ATTR_USE_OVERDUE_TIME = <span class="string">"use-overdue-time"</span>;<a name="79" href="#79">79</a> <strong>protected</strong> <strong>final</strong> <strong>static</strong> Boolean DEFAULT_USE_OVERDUE_TIME = <strong>new</strong> Boolean(false); <a name="80" href="#80">80</a> <a name="81" href="#81">81</a> <em>/**<em>*</em></em><a name="82" href="#82">82</a> <em> * Constructor</em><a name="83" href="#83">83</a> <em> * </em><a name="84" href="#84">84</a> <em> * @param name The name of the module</em><a name="85" href="#85">85</a> <em> */</em><a name="86" href="#86">86</a> <strong>public</strong> <a href="../../../../org/archive/crawler/postprocessor/WaitEvaluator.html">WaitEvaluator</a>(String name) {<a name="87" href="#87">87</a> <strong>this</strong>(name, <a name="88" href="#88">88</a> <span class="string">"Evaluates how long to wait before fetching a URI again. "</span> +<a name="89" href="#89">89</a> <span class="string">"Typically, this processor should be in the post processing "</span> +<a name="90" href="#90">90</a> <span class="string">"chain. It will pass if another wait evaluator has already "</span> +<a name="91" href="#91">91</a> <span class="string">"processed the CrawlURI."</span>,<a name="92" href="#92">92</a> DEFAULT_INITIAL_WAIT_INTERVAL,<a name="93" href="#93">93</a> DEFAULT_MAX_WAIT_INTERVAL,<a name="94" href="#94">94</a> DEFAULT_MIN_WAIT_INTERVAL,<a name="95" href="#95">95</a> DEFAULT_UNCHANGED_FACTOR,<a name="96" href="#96">96</a> DEFAULT_CHANGED_FACTOR);<a name="97" href="#97">97</a> }<a name="98" href="#98">98</a> <a name="99" href="#99">99</a> <em>/**<em>*</em></em><a name="100" href="#100">100</a> <em> * Constructor</em><a name="101" href="#101">101</a> <em> * </em><a name="102" href="#102">102</a> <em> * @param name The name of the module</em><a name="103" href="#103">103</a> <em> * @param description Description of the module</em><a name="104" href="#104">104</a> <em> * @param default_inital_wait_interval The default value for initial wait</em><a name="105" href="#105">105</a> <em> * time</em><a name="106" href="#106">106</a> <em> * @param default_max_wait_interval The maximum value for wait time</em><a name="107" href="#107">107</a> <em> * @param default_min_wait_interval The minimum value for wait time</em><a name="108" href="#108">108</a> <em> * @param default_unchanged_factor The factor for changing wait times of</em><a name="109" href="#109">109</a> <em> * unchanged documents (will be multiplied by this value)</em><a name="110" href="#110">110</a> <em> * @param default_changed_factor The factor for changing wait times of</em><a name="111" href="#111">111</a> <em> * changed documents (will be divided by this value)</em><a name="112" href="#112">112</a> <em> */</em><a name="113" href="#113">113</a> <strong>public</strong> <a href="../../../../org/archive/crawler/postprocessor/WaitEvaluator.html">WaitEvaluator</a>(String name, String description,<a name="114" href="#114">114</a> Long <strong>default</strong>_inital_wait_interval,<a name="115" href="#115">115</a> Long <strong>default</strong>_max_wait_interval,<a name="116" href="#116">116</a> Long <strong>default</strong>_min_wait_interval,<a name="117" href="#117">117</a> Double <strong>default</strong>_unchanged_factor,<a name="118" href="#118">118</a> Double <strong>default</strong>_changed_factor){<a name="119" href="#119">119</a> <strong>super</strong>(name, description);<a name="120" href="#120">120</a> <a name="121" href="#121">121</a> addElementToDefinition(<strong>new</strong> <a href="../../../../org/archive/crawler/settings/SimpleType.html">SimpleType</a>(ATTR_INITIAL_WAIT_INTERVAL,<a name="122" href="#122">122</a> <span class="string">"The initial wait time between revisits. Will then be "</span> +<a name="123" href="#123">123</a> <span class="string">"updated according to crawler experiance. I.e. shorter "</span> +<a name="124" href="#124">124</a> <span class="string">"wait, visit more often, if document has changed between "</span> +<a name="125" href="#125">125</a> <span class="string">"visits, and vica versa."</span>,<a name="126" href="#126">126</a> <strong>default</strong>_inital_wait_interval));<a name="127" href="#127">127</a> addElementToDefinition(<strong>new</strong> <a href="../../../../org/archive/crawler/settings/SimpleType.html">SimpleType</a>(ATTR_MAX_WAIT_INTERVAL,<a name="128" href="#128">128</a> <span class="string">"The maximum settable wait time between revisits. Once a "</span> +<a name="129" href="#129">129</a> <span class="string">"URIs wait time reaches this value, it will not grow "</span> +<a name="130" href="#130">130</a> <span class="string">"further, regardless of subsequent visits that discover "</span> +<a name="131" href="#131">131</a> <span class="string">"no changes. Note that this does not ensure that the URI "</span> +<a name="132" href="#132">132</a> <span class="string">"does not wait any longer, since the crawler might be "</span> +<a name="133" href="#133">133</a> <span class="string">"'behind,' forcing a URI to wait until other URIs, "</span> +<a name="134" href="#134">134</a> <span class="string">"scheduled for earlier are completed.."</span>,<a name="135" href="#135">135</a> <strong>default</strong>_max_wait_interval));<a name="136" href="#136">136</a> addElementToDefinition(<strong>new</strong> <a href="../../../../org/archive/crawler/settings/SimpleType.html">SimpleType</a>(ATTR_MIN_WAIT_INTERVAL,<a name="137" href="#137">137</a> <span class="string">"The minum settable wait time between revisits. Once a "</span> +<a name="138" href="#138">138</a> <span class="string">"URIs wait time reaches this value, it will not be shortened "</span> +<a name="139" href="#139">139</a> <span class="string">"further, regardlesss of subsequent visits that discover "</span> +<a name="140" href="#140">140</a> <span class="string">"changes."</span>,<a name="141" href="#141">141</a> <strong>default</strong>_min_wait_interval));<a name="142" href="#142">142</a> addElementToDefinition(<strong>new</strong> <a href="../../../../org/archive/crawler/settings/SimpleType.html">SimpleType</a>(ATTR_DEFAULT_WAIT_INTERVAL,<a name="143" href="#143">143</a> <span class="string">"Fixed wait time for 'unknown' change status. I.e. wait time "</span> +<a name="144" href="#144">144</a> <span class="string">"for URIs whose content change detection is not available."</span>,⌨️ 快捷键说明
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