public class

ReflectiveLoadTimeWeaver

extends Object
implements LoadTimeWeaver
java.lang.Object
   ↳ org.springframework.instrument.classloading.ReflectiveLoadTimeWeaver

Class Overview

LoadTimeWeaver which uses reflection to delegate to an underlying ClassLoader with well-known transformation hooks. The underlying ClassLoader is expected to support the following weaving methods (as defined in the LoadTimeWeaver interface):

  • public void addTransformer(java.lang.instrument.ClassFileTransformer): for registering the given ClassFileTransformer on this ClassLoader
  • public ClassLoader getThrowawayClassLoader(): for obtaining a throwaway class loader for this ClassLoader (optional; ReflectiveLoadTimeWeaver will fall back to a SimpleThrowawayClassLoader if that method isn't available)

Please note that the above methods must reside in a class that is publicly accessible, although the class itself does not have to be visible to the application's class loader.

The reflective nature of this LoadTimeWeaver is particularly useful when the underlying ClassLoader implementation is loaded in a different class loader itself (such as the application server's class loader which is not visible to the web application). There is no direct API dependency between this LoadTimeWeaver adapter and the underlying ClassLoader, just a 'loose' method contract.

This is the LoadTimeWeaver to use in combination with Spring's TomcatInstrumentableClassLoader for Tomcat 5.0+ as well as with the Resin application server version 3.1+.

See Also

Summary

Public Constructors
ReflectiveLoadTimeWeaver()
Create a new ReflectiveLoadTimeWeaver for the current context class loader, which needs to support the required weaving methods.
ReflectiveLoadTimeWeaver(ClassLoader classLoader)
Create a new SimpleLoadTimeWeaver for the given class loader.
Public Methods
void addTransformer(ClassFileTransformer transformer)
Add a ClassFileTransformer to be applied by this LoadTimeWeaver.
ClassLoader getInstrumentableClassLoader()
Return a ClassLoader that supports instrumentation through AspectJ-style load-time weaving based on user-defined ClassFileTransformers.
ClassLoader getThrowawayClassLoader()
Return a throwaway ClassLoader, enabling classes to be loaded and inspected without affecting the parent ClassLoader.
[Expand]
Inherited Methods
From class java.lang.Object
From interface org.springframework.instrument.classloading.LoadTimeWeaver

Public Constructors

public ReflectiveLoadTimeWeaver ()

Create a new ReflectiveLoadTimeWeaver for the current context class loader, which needs to support the required weaving methods.

public ReflectiveLoadTimeWeaver (ClassLoader classLoader)

Create a new SimpleLoadTimeWeaver for the given class loader.

Parameters
classLoader the ClassLoader to delegate to for weaving (must support the required weaving methods).
Throws
IllegalStateException if the supplied ClassLoader does not support the required weaving methods

Public Methods

public void addTransformer (ClassFileTransformer transformer)

Add a ClassFileTransformer to be applied by this LoadTimeWeaver.

Parameters
transformer the ClassFileTransformer to add

public ClassLoader getInstrumentableClassLoader ()

Return a ClassLoader that supports instrumentation through AspectJ-style load-time weaving based on user-defined ClassFileTransformers.

May be the current ClassLoader, or a ClassLoader created by this LoadTimeWeaver instance.

Returns
  • the ClassLoader which will expose instrumented classes according to the registered transformers

public ClassLoader getThrowawayClassLoader ()

Return a throwaway ClassLoader, enabling classes to be loaded and inspected without affecting the parent ClassLoader.

Should not return the same instance of the ClassLoader returned from an invocation of getInstrumentableClassLoader().

Returns
  • a temporary throwaway ClassLoader; should return a new instance for each call, with no existing state