com.opensymphony.xwork2.util
Class ClassLoaderUtil

java.lang.Object
  com.opensymphony.xwork2.util.ClassLoaderUtil

public class ClassLoaderUtil
extends Object

This class is extremely useful for loading resources and classes in a fault tolerant manner that works across different applications servers. It has come out of many months of frustrating use of multiple application servers at Atlassian, please don't change things unless you're sure they're not going to break in one server or another! It was brought in from oscore trunk revision 147.

Version:

$Revision: 117 $

Author:

$Author: hani $

Nested Class Summary

protected static class

ClassLoaderUtil.AggregateIterator<E> Aggregates Enumeration instances into one iterator and filters out duplicates.

Constructor Summary

ClassLoaderUtil()

Method Summary

static URL	getResource(String resourceName, Class callingClass) Load a given resource.
static InputStream	getResourceAsStream(String resourceName, Class callingClass) This is a convenience method to load a resource as a stream.
static Iterator<URL>	getResources(String resourceName, Class callingClass, boolean aggregate) Load all resources with a given name, potentially aggregating all results from the searched classloaders.
static Class	loadClass(String className, Class callingClass) Load a class with a given name.

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassLoaderUtil

public ClassLoaderUtil()

Method Detail

getResources

public static Iterator<URL> getResources(String resourceName,
                                         Class callingClass,
                                         boolean aggregate)
                                  throws IOException

Load all resources with a given name, potentially aggregating all results from the searched classloaders. If no results are found, the resource name is prepended by '/' and tried again. This method will try to load the resources using the following methods (in order):

• From Thread.currentThread().getContextClassLoader()
• From ClassLoaderUtil.class.getClassLoader()
• callingClass.getClassLoader()

Parameters:

resourceName - The name of the resources to load

callingClass - The Class object of the calling object

Throws:

IOException

getResource

public static URL getResource(String resourceName,
                              Class callingClass)

Load a given resource. This method will try to load the resource using the following methods (in order):

• From Thread.currentThread().getContextClassLoader()
• From ClassLoaderUtil.class.getClassLoader()
• callingClass.getClassLoader()

Parameters:

resourceName - The name IllegalStateException("Unable to call ")of the resource to load

callingClass - The Class object of the calling object

getResourceAsStream

public static InputStream getResourceAsStream(String resourceName,
                                              Class callingClass)

This is a convenience method to load a resource as a stream. The algorithm used to find the resource is given in getResource()

Parameters:

resourceName - The name of the resource to load

callingClass - The Class object of the calling object

loadClass

public static Class loadClass(String className,
                              Class callingClass)
                       throws ClassNotFoundException

Load a class with a given name. It will try to load the class in the following order:

• From Thread.currentThread().getContextClassLoader()
• Using the basic Class.forName()
• From ClassLoaderUtil.class.getClassLoader()
• From the callingClass.getClassLoader()

Parameters:

className - The name of the class to load

callingClass - The Class object of the calling object

Throws:

ClassNotFoundException - If the class cannot be found anywhere.