// print the object on the top of the stack
public Assembler printObject() {
mv.visitFieldInsn(GETSTATIC, "java/lang/System", "out", "Ljava/io/PrintStream;");
mv.visitInsn(SWAP);
mv.visitMethodInsn(
INVOKEVIRTUAL, "java/io/PrintStream", "println", "(Ljava/lang/Object;)V", false);
return this;
}
/** 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 Assembler invokeInterface(String owner, String method, String desc) {
mv.visitMethodInsn(INVOKEVIRTUAL, owner, method, desc, true);
return this;
}
public Assembler invokeStatic(String owner, String method, String desc) {
mv.visitMethodInsn(INVOKESTATIC, owner, method, desc, false);
return this;
}
public Assembler invokeSpecial(String owner, String method, String desc) {
mv.visitMethodInsn(INVOKESPECIAL, owner, method, desc, false);
return this;
}
public Assembler invokeVirtual(String owner, String method, String desc) {
mv.visitMethodInsn(INVOKEVIRTUAL, owner, method, desc, false);
return this;
}