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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>CachedBdbMap xref</title><link type="text/css" rel="stylesheet" href="../../../stylesheet.css" /></head><body><div id="overview"><a href="../../../../apidocs/org/archive/util/CachedBdbMap.html">View Javadoc</a></div><pre><a name="1" href="#1">1</a> <em class="comment">/*<em class="comment"> CachedBdbMap</em></em><a name="2" href="#2">2</a> <em class="comment"> * </em><a name="3" href="#3">3</a> <em class="comment"> * $Id: CachedBdbMap.java 4926 2007-02-21 06:02:36Z gojomo $</em><a name="4" href="#4">4</a> <em class="comment"> * </em><a name="5" href="#5">5</a> <em class="comment"> * Created on Mar 24, 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/util/package-summary.html">org.archive.util</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.Serializable;<a name="30" href="#30">30</a> <strong>import</strong> java.lang.ref.PhantomReference;<a name="31" href="#31">31</a> <strong>import</strong> java.lang.ref.Reference;<a name="32" href="#32">32</a> <strong>import</strong> java.lang.ref.ReferenceQueue;<a name="33" href="#33">33</a> <strong>import</strong> java.lang.ref.SoftReference;<a name="34" href="#34">34</a> <strong>import</strong> java.lang.reflect.Field;<a name="35" href="#35">35</a> <strong>import</strong> java.util.AbstractMap;<a name="36" href="#36">36</a> <strong>import</strong> java.util.HashMap;<a name="37" href="#37">37</a> <strong>import</strong> java.util.Iterator;<a name="38" href="#38">38</a> <strong>import</strong> java.util.LinkedList;<a name="39" href="#39">39</a> <strong>import</strong> java.util.Map;<a name="40" href="#40">40</a> <strong>import</strong> java.util.Set;<a name="41" href="#41">41</a> <strong>import</strong> java.util.logging.Level;<a name="42" href="#42">42</a> <strong>import</strong> java.util.logging.Logger;<a name="43" href="#43">43</a> <a name="44" href="#44">44</a> <strong>import</strong> com.sleepycat.bind.EntryBinding;<a name="45" href="#45">45</a> <strong>import</strong> com.sleepycat.bind.serial.SerialBinding;<a name="46" href="#46">46</a> <strong>import</strong> com.sleepycat.bind.serial.StoredClassCatalog;<a name="47" href="#47">47</a> <strong>import</strong> com.sleepycat.bind.tuple.TupleBinding;<a name="48" href="#48">48</a> <strong>import</strong> com.sleepycat.collections.StoredSortedMap;<a name="49" href="#49">49</a> <strong>import</strong> com.sleepycat.je.Database;<a name="50" href="#50">50</a> <strong>import</strong> com.sleepycat.je.DatabaseConfig;<a name="51" href="#51">51</a> <strong>import</strong> com.sleepycat.je.DatabaseException;<a name="52" href="#52">52</a> <strong>import</strong> com.sleepycat.je.Environment;<a name="53" href="#53">53</a> <strong>import</strong> com.sleepycat.je.EnvironmentConfig;<a name="54" href="#54">54</a> <a name="55" href="#55">55</a> <em>/**<em>*</em></em><a name="56" href="#56">56</a> <em> * A BDB JE backed hashmap. It extends the normal BDB JE map implementation by</em><a name="57" href="#57">57</a> <em> * holding a cache of soft referenced objects. That is objects are not written</em><a name="58" href="#58">58</a> <em> * to disk until they are not referenced by any other object and therefore can be</em><a name="59" href="#59">59</a> <em> * Garbage Collected.</em><a name="60" href="#60">60</a> <em> * </em><a name="61" href="#61">61</a> <em> * @author John Erik Halse</em><a name="62" href="#62">62</a> <em> * @author stack</em><a name="63" href="#63">63</a> <em> * @author gojomo</em><a name="64" href="#64">64</a> <em> * </em><a name="65" href="#65">65</a> <em> */</em><a name="66" href="#66">66</a> <strong>public</strong> <strong>class</strong> CachedBdbMap<K,V> <strong>extends</strong> AbstractMap<K,V> <a name="67" href="#67">67</a> implements Map<K,V>, Serializable {<a name="68" href="#68">68</a> <a name="69" href="#69">69</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> <strong>long</strong> serialVersionUID = -8655539411367047332L;<a name="70" href="#70">70</a> <a name="71" href="#71">71</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> Logger logger =<a name="72" href="#72">72</a> Logger.getLogger(CachedBdbMap.<strong>class</strong>.getName());<a name="73" href="#73">73</a> <a name="74" href="#74">74</a> <em>/**<em>* The database name of the class definition catalog.*/</em></em><a name="75" href="#75">75</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> String CLASS_CATALOG = <span class="string">"java_class_catalog"</span>;<a name="76" href="#76">76</a> <a name="77" href="#77">77</a> <em>/**<em>*</em></em><a name="78" href="#78">78</a> <em> * A map of BDB JE Environments so that we reuse the Environment for</em><a name="79" href="#79">79</a> <em> * databases in the same directory.</em><a name="80" href="#80">80</a> <em> */</em><a name="81" href="#81">81</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> Map<String,DbEnvironmentEntry> dbEnvironmentMap = <a name="82" href="#82">82</a> <strong>new</strong> HashMap<String,DbEnvironmentEntry>();<a name="83" href="#83">83</a> <a name="84" href="#84">84</a> <em>/**<em>* The BDB JE environment used for this instance.</em></em><a name="85" href="#85">85</a> <em> */</em><a name="86" href="#86">86</a> <strong>private</strong> <strong>transient</strong> DbEnvironmentEntry dbEnvironment;<a name="87" href="#87">87</a> <a name="88" href="#88">88</a> <em>/**<em>* The BDB JE database used for this instance. */</em></em><a name="89" href="#89">89</a> <strong>protected</strong> <strong>transient</strong> Database db;<a name="90" href="#90">90</a> <a name="91" href="#91">91</a> <em>/**<em>* The Collection view of the BDB JE database used for this instance. */</em></em><a name="92" href="#92">92</a> <strong>protected</strong> <strong>transient</strong> StoredSortedMap diskMap;<a name="93" href="#93">93</a> <a name="94" href="#94">94</a> <em>/**<em>* The softreferenced cache */</em></em><a name="95" href="#95">95</a> <strong>private</strong> <strong>transient</strong> Map<K,SoftEntry<V>> memMap;<a name="96" href="#96">96</a> <a name="97" href="#97">97</a> <strong>protected</strong> <strong>transient</strong> ReferenceQueue<V> refQueue;<a name="98" href="#98">98</a> <a name="99" href="#99">99</a> <em>/**<em>* The number of objects in the diskMap StoredMap. </em></em><a name="100" href="#100">100</a> <em> * (Package access for unit testing.) */</em><a name="101" href="#101">101</a> <strong>protected</strong> <strong>int</strong> diskMapSize = 0;<a name="102" href="#102">102</a> <a name="103" href="#103">103</a> <em>/**<em>*</em></em><a name="104" href="#104">104</a> <em> * Count of times we got an object from in-memory cache.</em><a name="105" href="#105">105</a> <em> */</em><a name="106" href="#106">106</a> <strong>private</strong> <strong>long</strong> cacheHit = 0;<a name="107" href="#107">107</a> <a name="108" href="#108">108</a> <em>/**<em>*</em></em><a name="109" href="#109">109</a> <em> * Count of times the {@link CachedBdbMap#get(Object)} method was called.</em><a name="110" href="#110">110</a> <em> */</em><a name="111" href="#111">111</a> <strong>private</strong> <strong>long</strong> countOfGets = 0;<a name="112" href="#112">112</a> <a name="113" href="#113">113</a> <em>/**<em>*</em></em><a name="114" href="#114">114</a> <em> * Count of every time we went to the disk-based map AND we found an</em><a name="115" href="#115">115</a> <em> * object (Doesn't include accesses that came back null).</em><a name="116" href="#116">116</a> <em> */</em><a name="117" href="#117">117</a> <strong>private</strong> <strong>long</strong> diskHit = 0;<a name="118" href="#118">118</a> <a name="119" href="#119">119</a> <em>/**<em>*</em></em><a name="120" href="#120">120</a> <em> * Name of bdbje db.</em><a name="121" href="#121">121</a> <em> */</em><a name="122" href="#122">122</a> <strong>private</strong> String dbName = <strong>null</strong>;<a name="123" href="#123">123</a> <a name="124" href="#124">124</a> <em>/**<em>*</em></em><a name="125" href="#125">125</a> <em> * Reference to the Reference#referent Field.</em><a name="126" href="#126">126</a> <em> */</em><a name="127" href="#127">127</a> <strong>protected</strong> <strong>static</strong> Field referentField;<a name="128" href="#128">128</a> <strong>static</strong> {<a name="129" href="#129">129</a> <em class="comment">// We need access to the referent field in the PhantomReference.</em><a name="130" href="#130">130</a> <em class="comment">// For more on this trick, see</em><a name="131" href="#131">131</a> <em class="comment">// http://www.javaspecialists.co.za/archive/Issue098.html and for</em><a name="132" href="#132">132</a> <em class="comment">// discussion:</em><a name="133" href="#133">133</a> <em class="comment">// http://www.theserverside.com/tss?service=direct/0/NewsThread/threadViewer.markNoisy.link&sp=l29865&sp=l146901</em><a name="134" href="#134">134</a> <strong>try</strong> {<a name="135" href="#135">135</a> referentField = Reference.<strong>class</strong>.getDeclaredField(<span class="string">"referent"</span>);<a name="136" href="#136">136</a> referentField.setAccessible(<strong>true</strong>);<a name="137" href="#137">137</a> } <strong>catch</strong> (SecurityException e) {<a name="138" href="#138">138</a> <strong>throw</strong> <strong>new</strong> RuntimeException(e);<a name="139" href="#139">139</a> } <strong>catch</strong> (NoSuchFieldException e) {<a name="140" href="#140">140</a> <strong>throw</strong> <strong>new</strong> RuntimeException(e);<a name="141" href="#141">141</a> }<a name="142" href="#142">142</a> }<a name="143" href="#143">143</a> <a name="144" href="#144">144</a> <em>/**<em>*</em></em><a name="145" href="#145">145</a> <em> * Simple structure to keep needed information about a DB Environment.</em><a name="146" href="#146">146</a> <em> */</em><a name="147" href="#147">147</a> <strong>protected</strong> <strong>static</strong> <strong>class</strong> DbEnvironmentEntry {<a name="148" href="#148">148</a> Environment environment;<a name="149" href="#149">149</a> StoredClassCatalog classCatalog;<a name="150" href="#150">150</a> <strong>int</strong> openDbCount = 0;<a name="151" href="#151">151</a> File dbDir;<a name="152" href="#152">152</a> }<a name="153" href="#153">153</a> <a name="154" href="#154">154</a> <em>/**<em>*</em></em><a name="155" href="#155">155</a> <em> * Shudown default constructor.</em><a name="156" href="#156">156</a> <em> */</em>?? 快捷鍵說明
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