Package de.xima.fc.classloader

Class ChainedClassLoader

java.lang.Object

java.lang.ClassLoader

de.xima.fc.classloader.ChainedClassLoader

All Implemented Interfaces:

AutoCloseable

public final class ChainedClassLoader
extends ClassLoader
implements AutoCloseable

A class loader that combines several other class loaders.

• When searching for a class, it tries each class loader in order, and returns the class of the first class loader that can provide the class.
• When searching for a resources, it tries each class loader in order, and returns the resource of the first class loader that can provide the resource.
• When searching for multiple resources, it returns the resources of all class loaders.

When this class loader is closed, all chained loaders are closed if they implement AutoCloseable. Afterwards, classes cannot be loaded anymore.

Since:

7.0.11

Author:

XIMA MEDIA GmbH

Constructor Summary

Constructors

Constructor	Description
ChainedClassLoader(ClassLoader[] classLoaders)	Creates a new chained class loader that combines the given loaders.
ChainedClassLoader(Iterable<ClassLoader> classLoaders)	Creates a new chained class loader that combines the given loaders.

Method Summary

Modifier and Type	Method	Description
static ClassLoader	chain(ClassLoader[] classLoaders)	Creates a new class loader that combines the given loaders.
static ClassLoader	chain(Iterable<ClassLoader> classLoaders)	Creates a new class loader that combines the given loaders.
void	close()	Closes all chained loaders if they implement AutoCloseable.
List<ClassLoader>	getClassLoaders()	Returns all class loaders which this class loader combines.
URL	getResource(String name)
Enumeration<URL>	getResources(String name)
Class<?>	loadClass(String name)

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findClass, findLibrary, findLoadedClass, findResource, findResource, findResources, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResourceAsStream, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

ChainedClassLoader

public ChainedClassLoader(ClassLoader[] classLoaders)

Creates a new chained class loader that combines the given loaders.

Parameters:

classLoaders - Loaders to chain.

ChainedClassLoader

public ChainedClassLoader(Iterable<ClassLoader> classLoaders)

Creates a new chained class loader that combines the given loaders.

Parameters:

classLoaders - Loaders to chain.

Method Detail

close

public void close()
           throws Exception

Closes all chained loaders if they implement AutoCloseable. Afterwards, classes cannot be loaded anymore.

The method makes a best effort attempt to close all opened files, by catching Exceptions internally. Unchecked exceptions and errors are not caught. Calling close on an already closed loader has no effect.

Specified by:

close in interface AutoCloseable

Throws:

Exception - If closing any file opened by this class loader resulted in an Exception. Any such exceptions are caught internally. If only one is caught, then it is re-thrown. If more than one exception is caught, then the second and following exceptions are added as suppressed exceptions of the first one caught, which is then re-thrown.

getClassLoaders

public List<ClassLoader> getClassLoaders()

Returns all class loaders which this class loader combines. Note: the returned list is unmodifiable.

Returns:

The class loaders that are chained by this class loader.

getResource

public URL getResource(String name)

Overrides:

getResource in class ClassLoader

getResources

public Enumeration<URL> getResources(String name)
                              throws IOException

Overrides:

getResources in class ClassLoader

Throws:

IOException

loadClass

public Class<?> loadClass(String name)
                   throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

chain

public static ClassLoader chain(ClassLoader[] classLoaders)

Creates a new class loader that combines the given loaders. This method makes no guarantess regarding which sub class of ClassLoader is returned.

Parameters:

classLoaders - Loaders to chain.

Returns:

A class loader that combines the given loaders.

chain

public static ClassLoader chain(Iterable<ClassLoader> classLoaders)

Creates a new class loader that combines the given loaders. This method makes no guarantess regarding which sub class of ClassLoader is returned.

Parameters:

classLoaders - Loaders to chain.

Returns:

A class loader that combines the given loaders.