Package org.apache.nutch.plugin

Class Plugin

java.lang.Object

org.apache.nutch.plugin.Plugin

public class Plugin
extends Object

A nutch-plugin is an container for a set of custom logic that provide extensions to the nutch core functionality or another plugin that provides an API for extending. A plugin can provide one or a set of extensions. Extensions are components that can be dynamically installed as a kind of listener to extension points. Extension points are a kind of publisher that provide a API and invoke one or a set of installed extensions. Each plugin may extend the base Plugin. Plugin instances are used as the point of life cycle management of plugin related functionality. The Plugin will be started up and shutdown by the nutch plugin management system. A possible usecase of the Plugin implementation is to create or close a database connection.

Author:

joa23

Field Summary

Fields

Modifier and Type	Field	Description
protected Configuration	conf

Constructor Summary

Constructors

Constructor	Description
Plugin(PluginDescriptor pDescriptor, Configuration conf)	Overloaded constructor

Method Summary

Modifier and Type	Method	Description
protected void	finalize()
PluginDescriptor	getDescriptor()	Returns the plugin descriptor
void	shutDown()	Shutdown the plugin.
void	startUp()	Will be invoked until plugin start up.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

conf

protected Configuration conf

Constructor Details

Plugin

public Plugin(PluginDescriptor pDescriptor,
 Configuration conf)

Overloaded constructor

Parameters:

pDescriptor - a plugin descriptor

conf - a populated Configuration

Method Details

startUp

public void startUp()
             throws PluginRuntimeException

Will be invoked until plugin start up. Since the nutch-plugin system use lazy loading the start up is invoked until the first time a extension is used.

Throws:

PluginRuntimeException - If the startup was without successs.

shutDown

public void shutDown()
              throws PluginRuntimeException

Shutdown the plugin. This happens until nutch will be stopped.

Throws:

PluginRuntimeException - if a problems occurs until shutdown the plugin.

getDescriptor

public PluginDescriptor getDescriptor()

Returns the plugin descriptor

Returns:

PluginDescriptor

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable