org.springframework.instrument.classloading

Class WeavingTransformer

java.lang.Object

org.springframework.instrument.classloading.WeavingTransformer

public class WeavingTransformer
extends java.lang.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

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.ClassLoader	classLoader
private java.util.List<java.lang.instrument.ClassFileTransformer>	transformers

Constructor Summary

Constructors

Constructor and Description
WeavingTransformer(java.lang.ClassLoader classLoader) Create a new WeavingTransformer for the given class loader.

Method Summary

Modifier and Type	Method and Description
void	addTransformer(java.lang.instrument.ClassFileTransformer transformer) Add a class file transformer to be applied by this weaver.
byte[]	transformIfNecessary(java.lang.String className, byte[] bytes) Apply transformation on a given class byte definition.
byte[]	transformIfNecessary(java.lang.String className, java.lang.String internalName, byte[] bytes, java.security.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

Field Detail

classLoader

private final java.lang.ClassLoader classLoader

transformers

private final java.util.List<java.lang.instrument.ClassFileTransformer> transformers

Constructor Detail

WeavingTransformer

public WeavingTransformer(java.lang.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(java.lang.instrument.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(java.lang.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(java.lang.String className,
                                   java.lang.String internalName,
                                   byte[] bytes,
                                   java.security.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