Package org.jboss.shrinkwrap.impl.base

Class ServiceExtensionLoader

java.lang.Object

org.jboss.shrinkwrap.impl.base.ServiceExtensionLoader

All Implemented Interfaces:

ExtensionLoader

public class ServiceExtensionLoader
extends java.lang.Object
implements ExtensionLoader

ServiceExtensionLoader This class is the default strategy to load extensions when an instance of ExtensionLoader is not provided to the ConfigurationBuilder and the ConfigurationBuilder.build() method is invoked. If the ConfigurationBuilder doesn't provide any ClassLoader, ConfigurationBuilder.build() defaults to a one-element collection holding the TCCL. The classLoaders are used to find the provider-configuration file for the extension to be loaded in META-INF/services/. This provider-configuration file is used to make an instance of the SPI implementation and cached in cache.

Version:

$Revision: $

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.Map<java.lang.Class<?>,java.lang.Class<?>>	cache
private java.lang.Iterable<java.lang.ClassLoader>	classLoaders	ClassLoader used for loading extensions
private java.util.Map<java.lang.Class<?>,ExtensionWrapper>	extensionMappings
private static java.util.logging.Logger	log	Logger

Constructor Summary

Constructors

Constructor	Description
ServiceExtensionLoader(java.lang.Iterable<java.lang.ClassLoader> classLoaders)	Creates a new instance, using the specified ClassLoaders to create extensions

Method Summary

Modifier and Type	Method	Description
<T extends Assignable> ServiceExtensionLoader	addOverride(java.lang.Class<T> extensionClass, java.lang.Class<? extends T> extensionImplClass)	Add a Override to the normal Extension loading.
(package private) void	addToCache(java.lang.Class<?> extensionClass, java.lang.Class<?> extensionImplClass)
private <T extends Assignable> T	createExtension(java.lang.Class<T> extensionImplClass, Archive<?> archive)	Creates an instance of extensionImplClass using archive as the parameter for its one-argument list constructor.
private <T extends Assignable> T	createFromCache(java.lang.Class<T> extensionClass, Archive<?> archive)
private <T extends Assignable> T	createFromLoadExtension(java.lang.Class<T> extensionClass, Archive<?> archive)	Creates a new instance of a extensionClass implementation.
private <T extends Assignable> java.lang.reflect.Constructor<T>	findConstructor(java.lang.Class<T> extensionImplClass)	Finds a constructor with a one-argument list's element which implements Archive.
private <T extends Assignable> java.io.InputStream	findExtensionImpl(java.lang.Class<T> extensionClass)	Iterates through the classloaders to load the provider-configuration file for extensionClass in META-INF/services/ using its binary name.
<T extends Archive<T>> ArchiveFormat	getArchiveFormatFromExtensionMapping(java.lang.Class<T> type)	Gets the ArchiveFormat for the given type from the extensionMapping
private java.lang.Iterable<java.lang.ClassLoader>	getClassLoaders()
<T extends Assignable> java.lang.String	getExtensionFromExtensionMapping(java.lang.Class<T> type)	Gets the extension for the given type from the extensionMapping
(package private) <T extends Assignable> java.lang.Class<T>	getFromCache(java.lang.Class<T> extensionClass)
(package private) boolean	isCached(java.lang.Class<?> extensionClass)
boolean	isOverriden(java.lang.Class<?> extensionClass)	Check to see if a specific extension interface is beeing overloaded
<T extends Assignable> T	load(java.lang.Class<T> extensionClass, Archive<?> baseArchive)	Load a Extension.
private <T extends Assignable> java.lang.Class<T>	loadExtension(ExtensionWrapper extensionWrapper)	Loads the implementation class hold in ExtensionWrapper.implementingClassName
private <T extends Assignable> java.lang.Class<T>	loadExtensionClass(java.lang.String extensionClassName)	Delegates class loading of extensionClassName to ClassLoaderSearchUtilDelegator.findClassFromClassLoaders(String, Iterable) passing the extensionClassName and the instance's classLoaders.
private <T extends Assignable> ExtensionWrapper	loadExtensionMapping(java.lang.Class<T> extensionClass)	Finds the SPI configuration, wraps it into a ExtensionWrapper and loads it to extensionMappings.
private <T extends Assignable> ExtensionWrapper	loadExtensionWrapper(java.io.InputStream extensionStream, java.lang.Class<T> extensionClass)	Wraps the provider-configuration file extensionStream, the SPI extensionClass and its implementation class name into a ExtensionWrapper instance.

Methods inherited from class java.lang.Object

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

Field Detail

log

private static final java.util.logging.Logger log

Logger

cache

private java.util.Map<java.lang.Class<?>,java.lang.Class<?>> cache

extensionMappings

private java.util.Map<java.lang.Class<?>,ExtensionWrapper> extensionMappings

classLoaders

private final java.lang.Iterable<java.lang.ClassLoader> classLoaders

ClassLoader used for loading extensions

Constructor Detail

ServiceExtensionLoader

public ServiceExtensionLoader(java.lang.Iterable<java.lang.ClassLoader> classLoaders)
                       throws java.lang.IllegalArgumentException

Creates a new instance, using the specified ClassLoaders to create extensions

Parameters:

classLoaders -

Throws:

java.lang.IllegalArgumentException - If the ClassLoader is not specified

Method Detail

load

public <T extends Assignable> T load(java.lang.Class<T> extensionClass,
                                     Archive<?> baseArchive)
                              throws UnknownExtensionTypeException

Load a Extension.

Specified by:

load in interface ExtensionLoader

Parameters:

extensionClass - The Extension interface

baseArchive - The base archive to use

Returns:

a

Throws:

UnknownExtensionTypeException

See Also:

ExtensionLoader.load(java.lang.Class, org.jboss.shrinkwrap.api.Archive)

isCached

boolean isCached(java.lang.Class<?> extensionClass)

createFromCache

private <T extends Assignable> T createFromCache(java.lang.Class<T> extensionClass,
                                                 Archive<?> archive)

addToCache

void addToCache(java.lang.Class<?> extensionClass,
                java.lang.Class<?> extensionImplClass)

getFromCache

<T extends Assignable> java.lang.Class<T> getFromCache(java.lang.Class<T> extensionClass)

addOverride

public <T extends Assignable> ServiceExtensionLoader addOverride(java.lang.Class<T> extensionClass,
                                                                 java.lang.Class<? extends T> extensionImplClass)

Add a Override to the normal Extension loading. If a specific class is found to be overridden, the class will not be loaded using the normal strategy.

Specified by:

addOverride in interface ExtensionLoader

Type Parameters:

T - The type of Extension

Parameters:

extensionClass - The Extension interface class

extensionImplClass - The Extension implementation class

Returns:

this ExtensionLoader

See Also:

ExtensionLoader.addOverride(java.lang.Class, java.lang.Class)

getExtensionFromExtensionMapping

public <T extends Assignable> java.lang.String getExtensionFromExtensionMapping(java.lang.Class<T> type)

Gets the extension for the given type from the extensionMapping

Specified by:

getExtensionFromExtensionMapping in interface ExtensionLoader

Type Parameters:

T - The type of Extension

Parameters:

type - The Extension interface class

Returns:

the filename extension

See Also:

ExtensionLoader.getExtensionFromExtensionMapping(java.lang.Class)

getArchiveFormatFromExtensionMapping

public <T extends Archive<T>> ArchiveFormat getArchiveFormatFromExtensionMapping(java.lang.Class<T> type)

Gets the ArchiveFormat for the given type from the extensionMapping

Specified by:

getArchiveFormatFromExtensionMapping in interface ExtensionLoader

Type Parameters:

T - The type of Extension

Parameters:

type - The Extension interface class

Returns:

the archive format

See Also:

ExtensionLoader.getArchiveFormatFromExtensionMapping(java.lang.Class)

isOverriden

public boolean isOverriden(java.lang.Class<?> extensionClass)

Check to see if a specific extension interface is beeing overloaded

Parameters:

extensionClass - The ExtensionType interface class

Returns:

true if found

createFromLoadExtension

private <T extends Assignable> T createFromLoadExtension(java.lang.Class<T> extensionClass,
                                                         Archive<?> archive)

Creates a new instance of a extensionClass implementation. The implementation class is found in a provider-configuration file in META-INF/services/

Type Parameters:

T -

Parameters:

extensionClass -

archive -

Returns:

an instance of the extensionClass' implementation.

loadExtension

private <T extends Assignable> java.lang.Class<T> loadExtension(ExtensionWrapper extensionWrapper)

Loads the implementation class hold in ExtensionWrapper.implementingClassName

Type Parameters:

T -

Parameters:

extensionWrapper -

Returns:

loadExtensionMapping

private <T extends Assignable> ExtensionWrapper loadExtensionMapping(java.lang.Class<T> extensionClass)

Finds the SPI configuration, wraps it into a ExtensionWrapper and loads it to extensionMappings.

Type Parameters:

T -

Parameters:

extensionClass -

Returns:

findExtensionImpl

private <T extends Assignable> java.io.InputStream findExtensionImpl(java.lang.Class<T> extensionClass)

Iterates through the classloaders to load the provider-configuration file for extensionClass in META-INF/services/ using its binary name.

Type Parameters:

T -

Parameters:

extensionClass - SPI type for which the configuration file is looked for

Returns:

An InputStream representing extensionClass's configuration file

Throws:

java.lang.RuntimeException - if it doesn't find a provider-configuration file for extensionClass

UnknownExtensionTypeExceptionDelegator

loadExtensionWrapper

private <T extends Assignable> ExtensionWrapper loadExtensionWrapper(java.io.InputStream extensionStream,
                                                                     java.lang.Class<T> extensionClass)

Wraps the provider-configuration file extensionStream, the SPI extensionClass and its implementation class name into a ExtensionWrapper instance.

Type Parameters:

T -

Parameters:

extensionStream - - a bytes stream representation of the provider-configuration file

extensionClass - - SPI type

Returns:

a ExtensionWrapper instance

loadExtensionClass

private <T extends Assignable> java.lang.Class<T> loadExtensionClass(java.lang.String extensionClassName)

Delegates class loading of extensionClassName to ClassLoaderSearchUtilDelegator.findClassFromClassLoaders(String, Iterable) passing the extensionClassName and the instance's classLoaders.

Type Parameters:

T -

Parameters:

extensionClassName -

Returns:

createExtension

private <T extends Assignable> T createExtension(java.lang.Class<T> extensionImplClass,
                                                 Archive<?> archive)

Creates an instance of extensionImplClass using archive as the parameter for its one-argument list constructor.

Type Parameters:

T -

Parameters:

extensionImplClass -

archive -

Returns:

findConstructor

private <T extends Assignable> java.lang.reflect.Constructor<T> findConstructor(java.lang.Class<T> extensionImplClass)

Finds a constructor with a one-argument list's element which implements Archive.

Type Parameters:

T -

Parameters:

extensionImplClass - - Implementation of Assignable with a one-argument list's element which implements Archive.

Returns:

getClassLoaders

private java.lang.Iterable<java.lang.ClassLoader> getClassLoaders()