/** Generate class bytes for java.lang.Runnable implementation and return the same. */
public byte[] generate(Method method, String className) {
int modifiers = method.getModifiers();
// make sure that the method is public static
// and accepts no arguments
if (!Modifier.isStatic(modifiers)
|| !Modifier.isPublic(modifiers)
|| method.getParameterTypes().length != 0) {
throw new IllegalArgumentException();
}
Class clazz = method.getDeclaringClass();
modifiers = clazz.getModifiers();
// make sure that the class is public as well
if (!Modifier.isPublic(modifiers)) {
throw new IllegalArgumentException();
}
ClassWriter cw = InstrumentUtils.newClassWriter();
cw.visit(
V1_1, ACC_PUBLIC, className, null, "java/lang/Object", new String[] {"java/lang/Runnable"});
// creates a MethodWriter for the (implicit) constructor
MethodVisitor mw = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
// pushes the 'this' variable
mw.visitVarInsn(ALOAD, 0);
// invokes the super class constructor
mw.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");
mw.visitInsn(RETURN);
mw.visitMaxs(1, 1);
mw.visitEnd();
// creates a MethodWriter for the 'main' method
mw = cw.visitMethod(ACC_PUBLIC, "run", "()V", null, null);
// invokes the given method
mw.visitMethodInsn(
INVOKESTATIC,
Type.getInternalName(method.getDeclaringClass()),
method.getName(),
Type.getMethodDescriptor(method));
mw.visitInsn(RETURN);
mw.visitMaxs(1, 1);
mw.visitEnd();
return cw.toByteArray();
}
public static void main(final String[] args) throws Exception {
if (args.length != 1) {
System.err.println("Usage: java com.sun.btrace.runtime.ErrorReturnInstrumentor <class>");
System.exit(1);
}
args[0] = args[0].replace('.', '/');
FileInputStream fis = new FileInputStream(args[0] + ".class");
ClassReader reader = new ClassReader(new BufferedInputStream(fis));
FileOutputStream fos = new FileOutputStream(args[0] + ".class");
ClassWriter writer = InstrumentUtils.newClassWriter();
InstrumentUtils.accept(
reader,
new ClassVisitor(Opcodes.ASM4, writer) {
public MethodVisitor visitMethod(
int access, String name, String desc, String signature, String[] exceptions) {
MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
return new ErrorReturnInstrumentor(mv, null, args[0], args[0], access, name, desc);
}
});
fos.write(writer.toByteArray());
}