org.apache.nutch.plugin

Class PluginRepository

java.lang.Object

org.apache.nutch.plugin.PluginRepository

public class PluginRepository
extends Object

The plugin repositority is a registry of all plugins. At system boot up a repositority is builded by parsing the mainifest files of all plugins. Plugins that require not existing other plugins are not registed. For each plugin a plugin descriptor instance will be created. The descriptor represents all meta information about a plugin. So a plugin instance will be created later when it is required, this allow lazy plugin loading.

Author:

joa23

Field Summary

Fields

Modifier and Type	Field and Description
static org.apache.commons.logging.Log	LOG

Constructor Summary

Constructors

Constructor and Description
PluginRepository(Configuration conf)

Method Summary

Modifier and Type	Method and Description
void	finalize()
static PluginRepository	get(Configuration conf)
ExtensionPoint	getExtensionPoint(String pXpId) Returns a extension point indentified by a extension point id.
PluginDescriptor	getPluginDescriptor(String pPluginId) Returns the descriptor of one plugin identified by a plugin id.
PluginDescriptor[]	getPluginDescriptors() Returns all registed plugin descriptors.
Plugin	getPluginInstance(PluginDescriptor pDescriptor) Returns a instance of a plugin.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static final org.apache.commons.logging.Log LOG

Constructor Detail

PluginRepository

public PluginRepository(Configuration conf)
                 throws RuntimeException

Throws:

PluginRuntimeException

RuntimeException

See Also:

Object.Object()

Method Detail

get

public static PluginRepository get(Configuration conf)

Returns:

a cached instance of the plugin repository

getPluginDescriptors

public PluginDescriptor[] getPluginDescriptors()

Returns all registed plugin descriptors.

Returns:

PluginDescriptor[]

getPluginDescriptor

public PluginDescriptor getPluginDescriptor(String pPluginId)

Returns the descriptor of one plugin identified by a plugin id.

Parameters:

pPluginId -

Returns:

PluginDescriptor

getExtensionPoint

public ExtensionPoint getExtensionPoint(String pXpId)

Returns a extension point indentified by a extension point id.

Parameters:

pXpId -

Returns:

a extentsion point

getPluginInstance

public Plugin getPluginInstance(PluginDescriptor pDescriptor)
                         throws PluginRuntimeException

Returns a instance of a plugin. Plugin instances are cached. So a plugin exist only as one instance. This allow a central management of plugin own resources. After creating the plugin instance the startUp() method is invoked. The plugin use a own classloader that is used as well by all instance of extensions of the same plugin. This class loader use all exported libraries from the dependend plugins and all plugin libraries.

Parameters:

pDescriptor -

Returns:

Plugin

Throws:

PluginRuntimeException

finalize

public void finalize()
              throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable