org.springframework.instrument.classloading
Class WeavingTransformer

java.lang.Object
  org.springframework.instrument.classloading.WeavingTransformer

public class WeavingTransformer
extends Object

ClassFileTransformer-based weaver, allowing for a list of transformers to be applied on a class byte array. Normally used inside class loaders.

Note: This class is deliberately implemented for minimal external dependencies, since it is included in weaver jars (to be deployed into application servers).

Since:

2.0

Author:

Rod Johnson, Costin Leau, Juergen Hoeller

Constructor Summary

WeavingTransformer()
Create a new WeavingTransformer for the current context class loader.

WeavingTransformer(ClassLoader classLoader)
Create a new WeavingTransformer for the given class loader.

Method Summary

void	addTransformer(ClassFileTransformer transformer) Add a class file transformer to be applied by this weaver.
protected ClassLoader	getDefaultClassLoader() See ClassUtils.
byte[]	transformIfNecessary(String className, byte[] bytes) Apply transformation on a given class byte definition.
byte[]	transformIfNecessary(String className, String internalName, byte[] bytes, ProtectionDomain pd) Apply transformation on a given class byte definition.

Methods inherited from class java.lang.Object

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

Constructor Detail

WeavingTransformer

public WeavingTransformer()

Create a new WeavingTransformer for the current context class loader.

WeavingTransformer

public WeavingTransformer(ClassLoader classLoader)

Create a new WeavingTransformer for the given class loader.

Parameters:

classLoader - the ClassLoader to build a transformer for

Method Detail

addTransformer

public void addTransformer(ClassFileTransformer transformer)

Add a class file transformer to be applied by this weaver.

Parameters:

transformer - the class file transformer to register

transformIfNecessary

public byte[] transformIfNecessary(String className,
                                   byte[] bytes)

Apply transformation on a given class byte definition. The method will always return a non-null byte array (if no transformation has taken place the array content will be identical to the original one).

Parameters:

className - the full qualified name of the class in dot format (i.e. some.package.SomeClass)

bytes - class byte definition

Returns:

(possibly transformed) class byte definition

transformIfNecessary

public byte[] transformIfNecessary(String className,
                                   String internalName,
                                   byte[] bytes,
                                   ProtectionDomain pd)

Apply transformation on a given class byte definition. The method will always return a non-null byte array (if no transformation has taken place the array content will be identical to the original one).

Parameters:

className - the full qualified name of the class in dot format (i.e. some.package.SomeClass)

internalName - class name internal name in / format (i.e. some/package/SomeClass)

bytes - class byte definition

pd - protection domain to be used (can be null)

Returns:

(possibly transformed) class byte definition

getDefaultClassLoader

protected ClassLoader getDefaultClassLoader()

See ClassUtils. We don't depend on that to avoid pulling in more of Spring.

See Also:

ClassUtils.getDefaultClassLoader()