org.datanucleus.enhancer

Class DataNucleusClassFileTransformer

java.lang.Object

org.datanucleus.enhancer.DataNucleusClassFileTransformer

All Implemented Interfaces:

ClassFileTransformer

public class DataNucleusClassFileTransformer
extends Object
implements ClassFileTransformer

Entry Point (as per Java) for transforming classes at runtime. Before loading classes, the JVM invokes the ClassFileTranformer to transform the class. Will never process classes in packages "java.", "javax.", "org.datanucleus." (when not "test" or "samples"). Accepts the following (optional) arguments

• api : JDO, JPA - default=JDO
• generatePK : true, false - default=true
• generateConstructor : true, false - default=true
• detachListener : true, false - default=false
• default args : package names of classes to be enhanced when encountered

Field Summary

Fields

Modifier and Type	Field and Description
protected RuntimeEnhancer	enhancer

Constructor Summary

Constructors

Constructor and Description
DataNucleusClassFileTransformer(String arguments, Map contextProps)

Method Summary

Modifier and Type	Method and Description
static void	premain(String agentArguments, Instrumentation instrumentation)
byte[]	transform(ClassLoader loader, String className, Class classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) Invoked when a class is being loaded or redefined.

Methods inherited from class java.lang.Object

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

Field Detail

enhancer

protected RuntimeEnhancer enhancer

Constructor Detail

DataNucleusClassFileTransformer

public DataNucleusClassFileTransformer(String arguments,
                                       Map contextProps)

Method Detail

premain

public static void premain(String agentArguments,
                           Instrumentation instrumentation)

transform

public byte[] transform(ClassLoader loader,
                        String className,
                        Class classBeingRedefined,
                        ProtectionDomain protectionDomain,
                        byte[] classfileBuffer)
                 throws IllegalClassFormatException

Invoked when a class is being loaded or redefined. The implementation of this method may transform the supplied class file and return a new replacement class file.

Specified by:

transform in interface ClassFileTransformer

Parameters:

loader - The defining loader of the class to be transformed, may be null if the bootstrap loader

className - The name of the class in the internal form of fully qualified class and interface names

classBeingRedefined - If this is a redefine, the class being redefined, otherwise null

protectionDomain - The protection domain of the class being defined or redefined

classfileBuffer - The input byte buffer in class file format - must not be modified

Returns:

A well-formed class file buffer (the result of the transform), or null if no transform is performed

Throws:

IllegalClassFormatException - If the input does not represent a well-formed class file