Currently, I am working on research about refactoring tasks and its prioritization. I need to examine effects of each task (for example, move method, extract method, delete method) and to do some calculation on class and project level.

What is the best way of approaching these tasks manually, on code level?

I was thinking on building Eclipse plugin on top of its main application that open refactor menu and do refactoring tasks, but it doesn't seem good method, I need closer relation to code of each class.

Other way, I was thinking to build a plugin that parses each class and its references and does ref. tasks while parsing? This approach seems more appropriate to me since I need to automate the process and do some calculation.

What is the common way of programming/coding refactoring tasks (move, extract and delete method)? I am working on Java.