public TransformContext(String transformerClass, String filterPackage) {
classPool = new ClassPool(ClassPool.getDefault());
try {
transformer =
(ClassTransformer)
Class.forName(transformerClass, true, Thread.currentThread().getContextClassLoader())
.newInstance();
} catch (InstantiationException | IllegalAccessException | ClassNotFoundException e) {
throw new IllegalStateException(e);
}
transformer.setFilterPackageName(filterPackage);
transformer.setLogger(
new ILogger() {
@Override
public void warn(String message, Throwable throwable) {}
@Override
public void warn(String message) {}
@Override
public void info(String message, Throwable throwable) {}
@Override
public void info(String message) {}
@Override
public void error(String message, Throwable throwable) {}
@Override
public void error(String message) {}
@Override
public void debug(String message, Throwable throwable) {}
@Override
public void debug(String message) {}
@Override
public void addMessage(File file, int line, int pos, String message, Throwable e) {}
});
}
public byte[] transform(String className) {
if (transformer.filterClassName(className)) {
try {
CtClass classToTransform = classPool.get(className);
if (!classToTransform.isFrozen() && transformer.filterCtClass(classToTransform)) {
transformer.applyTransformations(classPool, classToTransform);
classToTransform.getClassFile().compact();
classToTransform.rebuildClassFile();
try (ByteArrayOutputStream baos = new ByteArrayOutputStream(4096);
DataOutputStream out = new DataOutputStream(new BufferedOutputStream(baos))) {
classToTransform.toBytecode(out);
out.flush();
return baos.toByteArray();
} catch (IOException | CannotCompileException e) {
throw new IllegalStateException(e);
}
}
} catch (NotFoundException e) {
throw new IllegalStateException(e);
}
}
return null;
}
@Override
public void generateClass(final ClassVisitor v) throws Exception {
t.setTarget(v);
gen.generateClass(t);
}
public void setTarget(ClassVisitor target) {
pass.setTarget(target);
direct = target;
}