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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>ExternalImplDecideRule xref</title><link type="text/css" rel="stylesheet" href="../../../../stylesheet.css" /></head><body><div id="overview"><a href="../../../../../apidocs/org/archive/crawler/deciderules/ExternalImplDecideRule.html">View Javadoc</a></div><pre><a name="1" href="#1">1</a> <em class="comment">/*<em class="comment"> ExternalImplDecideRule</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 May 25, 2005</em><a name="4" href="#4">4</a> <em class="comment"> *</em><a name="5" href="#5">5</a> <em class="comment"> * Copyright (C) 2005 Internet Archive.</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/deciderules/package-summary.html">org.archive.crawler.deciderules</a>;<a name="24" href="#24">24</a> <a name="25" href="#25">25</a> <strong>import</strong> java.util.logging.Logger;<a name="26" href="#26">26</a> <a name="27" href="#27">27</a> <strong>import</strong> javax.management.AttributeNotFoundException;<a name="28" href="#28">28</a> <a name="29" href="#29">29</a> <strong>import</strong> org.archive.crawler.settings.SimpleType;<a name="30" href="#30">30</a> <a name="31" href="#31">31</a> <em>/**<em>*</em></em><a name="32" href="#32">32</a> <em> * A rule that can be configured to take alternate implementations</em><a name="33" href="#33">33</a> <em> * of the ExternalImplInterface.</em><a name="34" href="#34">34</a> <em> * If no implementation specified, or none found, returns</em><a name="35" href="#35">35</a> <em> * configured decision.</em><a name="36" href="#36">36</a> <em> * @author stack</em><a name="37" href="#37">37</a> <em> * @version $Date: 2005/05/26 02:07:09 $, $Revision: 1.1 $</em><a name="38" href="#38">38</a> <em> */</em><a name="39" href="#39">39</a> <strong>public</strong> <strong>class</strong> <a href="../../../../org/archive/crawler/deciderules/ExternalImplDecideRule.html">ExternalImplDecideRule</a><a name="40" href="#40">40</a> <strong>extends</strong> <a href="../../../../org/archive/crawler/deciderules/PredicatedDecideRule.html">PredicatedDecideRule</a> {<a name="41" href="#41">41</a> <strong>private</strong> <strong>static</strong> <strong>final</strong> Logger LOGGER =<a name="42" href="#42">42</a> Logger.getLogger(ExternalImplDecideRule.<strong>class</strong>.getName());<a name="43" href="#43">43</a> <strong>static</strong> <strong>final</strong> String ATTR_IMPLEMENTATION = <span class="string">"implementation-class"</span>;<a name="44" href="#44">44</a> <strong>private</strong> <a href="../../../../org/archive/crawler/deciderules/ExternalImplInterface.html">ExternalImplInterface</a> implementation = <strong>null</strong>;<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> * @param name Name of this rule.</em><a name="48" href="#48">48</a> <em> */</em><a name="49" href="#49">49</a> <strong>public</strong> <a href="../../../../org/archive/crawler/deciderules/ExternalImplDecideRule.html">ExternalImplDecideRule</a>(String name) {<a name="50" href="#50">50</a> <strong>super</strong>(name);<a name="51" href="#51">51</a> setDescription(<span class="string">"ExternalImplDecideRule. Rule that "</span> +<a name="52" href="#52">52</a> <span class="string">"instantiates implementations of the ExternalImplInterface. "</span> +<a name="53" href="#53">53</a> <span class="string">"The implementation needs to be present on the classpath. "</span> +<a name="54" href="#54">54</a> <span class="string">"On initialization, the implementation is instantiated ("</span> +<a name="55" href="#55">55</a> <span class="string">"assumption is that there is public default constructor)."</span>);<a name="56" href="#56">56</a> addElementToDefinition(<strong>new</strong> <a href="../../../../org/archive/crawler/settings/SimpleType.html">SimpleType</a>(ATTR_IMPLEMENTATION,<a name="57" href="#57">57</a> <span class="string">"Name of implementation of ExternalImplInterface class to "</span> +<a name="58" href="#58">58</a> <span class="string">"instantiate."</span>, <span class="string">""</span>));<a name="59" href="#59">59</a> }<a name="60" href="#60">60</a> <a name="61" href="#61">61</a> <strong>boolean</strong> evaluate(Object obj) {<a name="62" href="#62">62</a> <a href="../../../../org/archive/crawler/deciderules/ExternalImplInterface.html">ExternalImplInterface</a> impl = getConfiguredImplementation(obj);<a name="63" href="#63">63</a> <strong>return</strong> (impl != <strong>null</strong>)? impl.evaluate(obj): false;<a name="64" href="#64">64</a> }<a name="65" href="#65">65</a> <a name="66" href="#66">66</a> <em>/**<em>* </em></em><a name="67" href="#67">67</a> <em> * Get implementation, if one specified.</em><a name="68" href="#68">68</a> <em> * If none specified, will keep trying to find one. Will be messy</em><a name="69" href="#69">69</a> <em> * if the provided class is not-instantiable or not implementation</em><a name="70" href="#70">70</a> <em> * of ExternalImplInterface.</em><a name="71" href="#71">71</a> <em> * @param o A context object.</em><a name="72" href="#72">72</a> <em> * @return Instance of <code>ExternalImplInterface</code> or null.</em><a name="73" href="#73">73</a> <em> */</em><a name="74" href="#74">74</a> <strong>protected</strong> <strong>synchronized</strong> <a href="../../../../org/archive/crawler/deciderules/ExternalImplInterface.html">ExternalImplInterface</a><a name="75" href="#75">75</a> getConfiguredImplementation(Object o) {<a name="76" href="#76">76</a> <strong>if</strong> (<strong>this</strong>.implementation != <strong>null</strong>) {<a name="77" href="#77">77</a> <strong>return</strong> <strong>this</strong>.implementation;<a name="78" href="#78">78</a> }<a name="79" href="#79">79</a> <a href="../../../../org/archive/crawler/deciderules/ExternalImplInterface.html">ExternalImplInterface</a> result = <strong>null</strong>;<a name="80" href="#80">80</a> <strong>try</strong> {<a name="81" href="#81">81</a> String className =<a name="82" href="#82">82</a> (String)getAttribute(o, ATTR_IMPLEMENTATION);<a name="83" href="#83">83</a> <strong>if</strong> (className != <strong>null</strong> && className.length() != 0) {<a name="84" href="#84">84</a> Object obj = Class.forName(className).newInstance();<a name="85" href="#85">85</a> <strong>if</strong> (!(obj instanceof ExternalImplInterface)) {<a name="86" href="#86">86</a> LOGGER.severe(<span class="string">"Implementation "</span> + className + <a name="87" href="#87">87</a> <span class="string">" does not implement ExternalImplInterface"</span>);<a name="88" href="#88">88</a> }<a name="89" href="#89">89</a> result = (ExternalImplInterface)obj;<a name="90" href="#90">90</a> <strong>this</strong>.implementation = result;<a name="91" href="#91">91</a> }<a name="92" href="#92">92</a> } <strong>catch</strong> (AttributeNotFoundException e) {<a name="93" href="#93">93</a> LOGGER.severe(e.getMessage());<a name="94" href="#94">94</a> } <strong>catch</strong> (InstantiationException e) {<a name="95" href="#95">95</a> LOGGER.severe(e.getMessage());<a name="96" href="#96">96</a> } <strong>catch</strong> (IllegalAccessException e) {<a name="97" href="#97">97</a> LOGGER.severe(e.getMessage());<a name="98" href="#98">98</a> } <strong>catch</strong> (ClassNotFoundException e) {<a name="99" href="#99">99</a> LOGGER.severe(e.getMessage());<a name="100" href="#100">100</a> }<a name="101" href="#101">101</a> <strong>return</strong> result;<a name="102" href="#102">102</a> }<a name="103" href="#103">103</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
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