Bytecode enhancement for fields in a class

Question

Is it possible to add "hooks" to a class via bytecode enhancement that execute code whenever a class field is read or written? For example, I'd like to automatically set a "dirty" flag whenever a new value is assigned to a field.

If so, which libraries are best suited to implement this functionality?

Answer 1

Here is how to generate getters and setters using the ASM framework. That should get you started.

• http://asm.ow2.org/doc/faq.html#Q9

You can even let your bytecode-rewriter hook into the class-loader and do the rewriting on the fly.

Answer 2

I'd suggest you to read about AspectJ. Probably this is the tool you are looking for.