com.newrelic.agent.instrumentation.weaver

Class ClassLoaderClassTransformer

java.lang.Object

com.newrelic.agent.instrumentation.weaver.ClassLoaderClassTransformer

All Implemented Interfaces:

ClassMatchVisitorFactory, ContextClassTransformer, java.lang.instrument.ClassFileTransformer

public class ClassLoaderClassTransformer
extends java.lang.Object
implements ClassMatchVisitorFactory, ContextClassTransformer, java.lang.instrument.ClassFileTransformer

Patch all ClassLoaders so that each version of the loadClass method checks to see if the class name starts with "com.newrelic.". If it does we delegate to the Agent classloader to allow the classes to load properly on any ClassLoader. We first allow the classloader to try to load all classes (except our api classes), but anytime the original loadClass method throws a ClassNotFoundException we catch it and try to load the class through our classloader if it's one of ours. The reason we first let the classloader try to load the class is because some of our new weaved classes must be loaded through the classloader they're added to because they reference classes that can only be resolved through the original classloader. We always try to load our api classes through our classloader because there may be multiple copies of the api jar but we always want the agent's version to take precedence. This instrumentation is required to run the ClassTransformerService. It can only be turned off by disabling the ClassTransformerService.

Field Summary

Fields inherited from interface com.newrelic.agent.instrumentation.context.ClassMatchVisitorFactory

NO_OP_FACTORY

Constructor Summary

Constructors

Constructor and Description
ClassLoaderClassTransformer(InstrumentationProxy instrumentation, java.util.Set<java.lang.String> classloaderDelegationExcludes, java.util.Set<java.lang.String> classloaderDelegationIncludes)

Method Summary

Modifier and Type	Method and Description
org.objectweb.asm.ClassVisitor	newClassMatchVisitor(java.lang.ClassLoader loader, java.lang.Class<?> classBeingRedefined, org.objectweb.asm.ClassReader reader, org.objectweb.asm.ClassVisitor cv, InstrumentationContext context) Returns a chaining class visitor that applies matching logic to the class referenced by the class reader and classBeingRedefined.
void	start(java.lang.Class<?>[] loadedClasses)
byte[]	transform(java.lang.ClassLoader loader, java.lang.String className, java.lang.Class<?> classBeingRedefined, java.security.ProtectionDomain protectionDomain, byte[] classfileBuffer)
byte[]	transform(java.lang.ClassLoader loader, java.lang.String className, java.lang.Class<?> classBeingRedefined, java.security.ProtectionDomain protectionDomain, byte[] classfileBuffer, InstrumentationContext context, OptimizedClassMatcher.Match match)

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassLoaderClassTransformer

public ClassLoaderClassTransformer(InstrumentationProxy instrumentation,
                                   java.util.Set<java.lang.String> classloaderDelegationExcludes,
                                   java.util.Set<java.lang.String> classloaderDelegationIncludes)

Method Detail

start

public void start(java.lang.Class<?>[] loadedClasses)

newClassMatchVisitor

public org.objectweb.asm.ClassVisitor newClassMatchVisitor(java.lang.ClassLoader loader,
                                                           java.lang.Class<?> classBeingRedefined,
                                                           org.objectweb.asm.ClassReader reader,
                                                           org.objectweb.asm.ClassVisitor cv,
                                                           InstrumentationContext context)

Description copied from interface: ClassMatchVisitorFactory

Returns a chaining class visitor that applies matching logic to the class referenced by the class reader and classBeingRedefined. The match results are reported in the InstrumentationContext.

Specified by:

newClassMatchVisitor in interface ClassMatchVisitorFactory

transform

public byte[] transform(java.lang.ClassLoader loader,
                        java.lang.String className,
                        java.lang.Class<?> classBeingRedefined,
                        java.security.ProtectionDomain protectionDomain,
                        byte[] classfileBuffer)
                 throws java.lang.instrument.IllegalClassFormatException

Specified by:

transform in interface java.lang.instrument.ClassFileTransformer

Throws:

java.lang.instrument.IllegalClassFormatException

transform

public byte[] transform(java.lang.ClassLoader loader,
                        java.lang.String className,
                        java.lang.Class<?> classBeingRedefined,
                        java.security.ProtectionDomain protectionDomain,
                        byte[] classfileBuffer,
                        InstrumentationContext context,
                        OptimizedClassMatcher.Match match)
                 throws java.lang.instrument.IllegalClassFormatException

Specified by:

transform in interface ContextClassTransformer

Throws:

java.lang.instrument.IllegalClassFormatException