net.sf.jguiraffe.di.impl

Class DefaultClassLoaderProvider

java.lang.Object

net.sf.jguiraffe.di.impl.DefaultClassLoaderProvider

All Implemented Interfaces:

ClassLoaderProvider

public class DefaultClassLoaderProvider
extends Object
implements ClassLoaderProvider

A default implementation of the ClassLoaderProvider interface.

This is a straight-forward (but thread-safe) implementation of all the methods defined by the ClassLoaderProvider interface. Class loaders registered at this object are stored in a map. A default class loader name can be set. If none has been set, the class loader that loaded this class is returned as default class loader.

Per default, classes of the library (starting with the prefix net.sf.jguiraffe) are always loaded by the class loader which loaded this class. This makes sense for instance in an OSGi environment: it allows access even to internal implementation classes. This behavior can be disabled by setting the handleInternalClasses property to false. Then the selected class loader is used to load all classes.

Version:

$Id: DefaultClassLoaderProvider.java 211 2012-07-10 19:49:13Z oheger $

Author:

Oliver Heger

Field Summary

Fields inherited from interface net.sf.jguiraffe.di.ClassLoaderProvider

CONTEXT_CLASS_LOADER

Constructor Summary

Constructors

Constructor and Description
DefaultClassLoaderProvider() Creates a new instance of DefaultClassLoaderProvider.
DefaultClassLoaderProvider(boolean fHandleInternalClasses) Creates a new instance of DefaultClassLoaderProvider and sets the flag whether internal classes should be handled in a special way.

Method Summary

Modifier and Type	Method and Description
Set<String>	classLoaderNames() Returns a set with the names of the class loaders that have been registered at this object.
ClassLoader	getClassLoader(String name) Returns the class loader specified by the given symbolic name.
String	getDefaultClassLoaderName() Returns the name of the default class loader.
boolean	isHandleInternalClasses() Returns a flag whether internal library classes are handled in a special way by this class loader provider.
Class<?>	loadClass(String name, String loaderRef) Loads the class with the specified name using the class loader identified by the given symbolic reference.
void	registerClassLoader(String name, ClassLoader loader) Allows to register a class loader under a symbolic name.
void	setDefaultClassLoaderName(String loaderName) Sets the name of the default class loader.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultClassLoaderProvider

public DefaultClassLoaderProvider()

Creates a new instance of DefaultClassLoaderProvider.

DefaultClassLoaderProvider

public DefaultClassLoaderProvider(boolean fHandleInternalClasses)

Creates a new instance of DefaultClassLoaderProvider and sets the flag whether internal classes should be handled in a special way.

Parameters:

fHandleInternalClasses - the value of the flag

Since:

1.2

Method Detail

isHandleInternalClasses

public boolean isHandleInternalClasses()

Returns a flag whether internal library classes are handled in a special way by this class loader provider. If this property is true, all classes belonging to this library are loaded by the class loader which also loaded this class.

Returns:

true if library classes are handled in a special way, false otherwise

Since:

1.2

classLoaderNames

public Set<String> classLoaderNames()

Returns a set with the names of the class loaders that have been registered at this object. All these names can be passed into the getClassLoader() method.

Specified by:

classLoaderNames in interface ClassLoaderProvider

Returns:

a set with the names of the class loaders registered at this object

getClassLoader

public ClassLoader getClassLoader(String name)

Returns the class loader specified by the given symbolic name. This method supports all variants: the default class loader (in this case the name is null), the context class loader, and a registered class loader.

Specified by:

getClassLoader in interface ClassLoaderProvider

Parameters:

name - the name of the class loader

Returns:

the corresponding class loader

Throws:

InjectionException - if the class loader cannot be resolved

getDefaultClassLoaderName

public String getDefaultClassLoaderName()

Returns the name of the default class loader. Result can be null if no default class loader name has been set so far.

Specified by:

getDefaultClassLoaderName in interface ClassLoaderProvider

Returns:

the name of the default class loader

See Also:

#setDefaultClassLoader(ClassLoader)

loadClass

public Class<?> loadClass(String name,
                          String loaderRef)

Loads the class with the specified name using the class loader identified by the given symbolic reference.

Specified by:

loadClass in interface ClassLoaderProvider

Parameters:

name - the class of the name to be loaded

loaderRef - determines the class loader to be used

Returns:

the loaded class

Throws:

InjectionException - if the class cannot be loaded

registerClassLoader

public void registerClassLoader(String name,
                                ClassLoader loader)

Allows to register a class loader under a symbolic name.

Specified by:

registerClassLoader in interface ClassLoaderProvider

Parameters:

name - the name of the class loader (must not be null)

loader - the class loader to be registered; can be null, then the class loader with the given name will be removed

Throws:

IllegalArgumentException - if the name is null

setDefaultClassLoaderName

public void setDefaultClassLoaderName(String loaderName)

Sets the name of the default class loader. Applications can here specify the name of a class loader they have registered or the reserved name ClassLoaderProvider.CONTEXT_CLASS_LOADER for the context class loader. A value of null causes getClassLoader(String) to fall back to the class loader which loaded this class.

Specified by:

setDefaultClassLoaderName in interface ClassLoaderProvider

Parameters:

loaderName - the new default class loader