public byte[] transform(
ClassLoader loader,
String classname,
Class<?> classBeingRedefined,
ProtectionDomain protectionDomain,
byte[] classfileBuffer) {
boolean someoneTouchedTheBytecode = false;
TransformerInfo[] transformerList = getSnapshotTransformerList();
byte[] bufferToUse = classfileBuffer;
// order matters, gotta run 'em in the order they were added
for (int x = 0; x < transformerList.length; x++) {
TransformerInfo transformerInfo = transformerList[x];
ClassFileTransformer transformer = transformerInfo.transformer();
byte[] transformedBytes = null;
try {
transformedBytes =
transformer.transform(
loader, classname, classBeingRedefined, protectionDomain, bufferToUse);
} catch (Throwable t) {
// don't let any one transformer mess it up for the others.
// This is where we need to put some logging. What should go here? FIXME
}
if (transformedBytes != null) {
someoneTouchedTheBytecode = true;
bufferToUse = transformedBytes;
}
}
// if someone modified it, return the modified buffer.
// otherwise return null to mean "no transforms occurred"
byte[] result;
if (someoneTouchedTheBytecode) {
result = bufferToUse;
} else {
result = null;
}
return result;
}
/*
* ClassFileLoadHook event handler method
*/
private byte[] transform(
ClassLoader loader,
byte[] classNameBytes,
Class<?> classBeingRedefined,
ProtectionDomain protectionDomain,
byte[] classfileBuffer) {
byte[] source = classfileBuffer;
byte[] result = null;
byte[] trans = null;
String className = new String(classNameBytes);
for (ClassFileTransformer t : transformers) {
try {
trans = t.transform(loader, className, classBeingRedefined, protectionDomain, source);
if (null != trans && 0 != trans.length) {
result = trans;
source = trans;
}
} catch (Exception e) {
// nothing to do, just continue~
}
}
return result;
}
@Override
public void onLoad(ClassPool pool, String classname)
throws NotFoundException, CannotCompileException {
logger.debug("loading className:{}", classname);
try {
// Find Modifier from agent and try transforming
String replace = classname.replace('.', '/');
ClassFileTransformer classFileTransformer = agent.getClassFileTransformer();
byte[] transform = classFileTransformer.transform(this.loader, replace, null, null, null);
if (transform != null) {
pool.makeClass(new ByteArrayInputStream(transform));
return;
}
} catch (IOException ex) {
throw new NotFoundException(classname + " not found. Caused:" + ex.getMessage(), ex);
} catch (IllegalClassFormatException ex) {
throw new RuntimeException(classname + " not found. Caused:" + ex.getMessage(), ex);
}
// find from modifierMap
findModifierMap(pool, classname);
}
@Override
public byte[] transform(
ClassLoader loader,
String className,
Class<?> redefinedClass,
ProtectionDomain protectionDomain,
byte[] bytecode)
throws IllegalClassFormatException {
byte[] data =
transformer.transform(loader, className, redefinedClass, protectionDomain, bytecode);
if (data != null) {
DebugUtils.dump(className, data, Kind.CLASS);
}
return data;
}