org.backsource.utils.lang
Class ReverseClassLoader

java.lang.Object
  java.lang.ClassLoader
      java.security.SecureClassLoader
          java.net.URLClassLoader
              org.backsource.utils.lang.ReverseClassLoader

public class ReverseClassLoader

extends java.net.URLClassLoader

A URLClassLoader wrapper that loads classes and resouces first from the leafs of the classloader tree, and not from the root as is the case with the sun classloader.

It is important to understand that all classes are loaded into the classloader wrapper and the new wrapper it created around its parent.

It is also important to know that if a URLClassLoader has a parent that is not a URLClassLoader, the normal classloading and resource finding mechanisms will be used.

May be really handy if you want to override a resource (or class) in a component loaded in leaf classloader, as is often the case in JBoss and Tomcat for example.

Version:

$Revision: 1.1.1.1 $

Author:

Peter Antman

Constructor Summary

ReverseClassLoader(java.net.URLClassLoader wrappedClassLoader)
Wrap a URLClassLoader.

Method Summary

java.net.URL	findResource(java.lang.String name)
java.net.URL	getResource(java.lang.String name) Get resource through a bottom up search.
java.lang.ClassLoader	getWrappedClassLoader()
protected java.lang.Class	loadClass(ReverseClassLoader cl, java.lang.String name)
java.lang.Class	loadClass(java.lang.String name) Load a class by looking in this classloader and searching upwards as long as the parent classloaders are URLClassloader.

Methods inherited from class java.net.URLClassLoader

addURL, definePackage, findClass, findResources, getPermissions, getURLs, newInstance, newInstance

Methods inherited from class java.security.SecureClassLoader

defineClass

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, definePackage, findLibrary, findLoadedClass, findSystemClass, getPackage, getPackages, getParent, 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

ReverseClassLoader

public ReverseClassLoader(java.net.URLClassLoader wrappedClassLoader)

Wrap a URLClassLoader.

The all URLs the classloader wikk be search first, and lodaded in this classloader, and not in the wrapped one.

Method Detail

getWrappedClassLoader

public java.lang.ClassLoader getWrappedClassLoader()

getResource

public java.net.URL getResource(java.lang.String name)

Get resource through a bottom up search. I.e try find the resource in the wrapped loader before proceding to the parent.

findResource

public java.net.URL findResource(java.lang.String name)

loadClass

public java.lang.Class loadClass(java.lang.String name)
                          throws java.lang.ClassNotFoundException

Load a class by looking in this classloader and searching upwards as long as the parent classloaders are URLClassloader.

It is important to notice that the classes will be loaded in this classloader or in any of its contsucted parents (also ReverseClassLoader) and not in the wrapped classloader.

Throws:

java.lang.ClassNotFoundException

loadClass

protected java.lang.Class loadClass(ReverseClassLoader cl,
                                    java.lang.String name)
                             throws java.lang.ClassNotFoundException

Throws:

java.lang.ClassNotFoundException