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Nutch 1.0 源代码分析[3] Plugin(2)

栏目:综合技术时间:2014-12-20 08:27:02

                                                                               Nutch 1.0 源代码分析[3] Plugin(2) 

                                                                                  来自: http://c.tieba.baidu.com/p/3439551436

在URLNormalizers构造函数中,有1句没有看:

this.extensionPoint =PluginRepository.get(conf).getExtensionPoint(

       URLNormalizer.X_POINT_ID);

    看1下PluginRepository.get函数:

public static synchronizedPluginRepository get(Configuration conf) {

    PluginRepository result = CACHE.get(conf);

    if (result ==null) {

       result = newPluginRepository(conf);

       CACHE.put(conf,result);

    }

    returnresult;

}

    先试着从CACHE取,如果没有被缓存过,那末就调用PluginRepository的构造函数:

publicPluginRepository(Configuration conf)throwsRuntimeException {

    fActivatedPlugins =newHashMap<String, Plugin>();

    fExtensionPoints =newHashMap<String, ExtensionPoint>();

    this.conf =conf;

    this.auto =conf.getBoolean("plugin.auto-activation",true);

    String[] pluginFolders = conf.getStrings("plugin.folders");

    PluginManifestParsermanifestParser = new PluginManifestParser(conf,

           this);

    Map<String, PluginDescriptor>allPlugins = manifestParser

           .parsePluginFolder(pluginFolders);

    Pattern excludes = Pattern.compile(conf.get("plugin.excludes",""));

    Pattern includes = Pattern.compile(conf.get("plugin.includes",""));

    Map<String, PluginDescriptor>filteredPlugins = filter(excludes,

           includes, allPlugins);

    fRegisteredPlugins =getDependencyCheckedPlugins(filteredPlugins,

           this.auto ?allPlugins : filteredPlugins);

    installExtensionPoints(fRegisteredPlugins);

    try {

       installExtensions(fRegisteredPlugins);

    } catch(PluginRuntimeException e) {

       LOG.fatal(e.toString());

       thrownewRuntimeException(e.getMessage());

    }

    displayStatus();

}

    这里拷贝1点《Nutch插件系统浅析》里的介绍:

1.       plugin.folders:插件所在的目录,缺省位置在 plugins 目录下。

<property>

   <name>plugin.folders</name>

   <value>plugins</value>

</property>

2.       plugin.auto-activation:当被配置为过滤(即不加载),但是又被其他插件依赖的时候,是不是自动启动,缺省为 true。

<property>

 <name>plugin.auto-activation</name>

 <value>true</value>

</property>

3.        plugin.includes:要包括的插件名称列表,支持正则表达式方式定义。

<property>


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