org.springframework.instrument.classloading
Class AbstractOverridingClassLoader

java.lang.Object
  java.lang.ClassLoader
      org.springframework.instrument.classloading.AbstractOverridingClassLoader

Direct Known Subclasses:

SimpleInstrumentableClassLoader, SimpleThrowawayClassLoader

public abstract class AbstractOverridingClassLoader
extends ClassLoader

Abstract superclass for class loaders that do not always delegate to their parent loader, as normal class loaders do. This enables, for example, instrumentation to be forced, or a "throwaway" class loader behavior, where selected classes are loaded by a child loader but not loaded by the parent.

Since:

2.0

Author:

Rod Johnson, Juergen Hoeller

Constructor Summary

protected

AbstractOverridingClassLoader(ClassLoader parent) Create a new AbstractOverridingClassLoader for the given class loader.

Method Summary

void	excludeClass(String className) Add a class name to exclude from overriding.
void	excludePackage(String packageName) Add a package name to exclude from overriding.
protected boolean	isEligibleForOverriding(String className) Determine whether the given class name is eligible for overriding by this class loader.
protected Class<?>	loadClass(String name, boolean resolve)
protected abstract byte[]	transformIfNecessary(String name, byte[] bytes) Transformation hook to be implemented by subclasses.

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLibrary, findLoadedClass, findResource, findResources, findSystemClass, getPackage, getPackages, getParent, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractOverridingClassLoader

protected AbstractOverridingClassLoader(ClassLoader parent)

Create a new AbstractOverridingClassLoader for the given class loader.

Parameters:

parent - the ClassLoader to build an overriding ClassLoader for

Method Detail

excludePackage

public void excludePackage(String packageName)

Add a package name to exclude from overriding.

Any class whose fully-qualified name starts with the name registered here will be handled by the parent ClassLoader in the usual fashion.

Parameters:

packageName - the package name to exclude

excludeClass

public void excludeClass(String className)

Add a class name to exclude from overriding.

Any class name registered here will be handled by the parent ClassLoader in the usual fashion.

Parameters:

className - the class name to exclude

loadClass

protected Class<?> loadClass(String name,
                             boolean resolve)
                      throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

isEligibleForOverriding

protected boolean isEligibleForOverriding(String className)

Determine whether the given class name is eligible for overriding by this class loader.

The default implementation excludes all specified packages and classes.

Parameters:

className - the class name to check

See Also:

excludePackage(java.lang.String), excludeClass(java.lang.String)

transformIfNecessary

protected abstract byte[] transformIfNecessary(String name,
                                               byte[] bytes)

Transformation hook to be implemented by subclasses.

Parameters:

name - FQN of class being transformed

bytes - class bytes

Returns:

transformed bytes. Return same as input bytes if the transformation produced no changes.