Whipping inherited code into shape

A couple of weeks ago Alain Ravet posted this summary of what he does when he reviews code to clean it up and clarify it. Though you may items to add or delete - this is a great starting point for approaching a new glob of code. Thank you Alain for letting me repost it here:

When I receive code, and before adding anything new to it, I always spend a little time (1 hour, 1 day) on "preparing" the code for the later modifications. This preparation is made in 2 steps:

• code cleaning
• code clarifying

Once I've done that, I understand the code/project better, and I can start adding tests, and functionalities.

Note: all the actions below are possible thanks to modern tools, and 100% safe refactorings => no need to write tests first.

Code cleaning : First, I run a quick and fully automated analysis of the code, with just a few rules:

• remove dead code (classes, methods).
• remove unused method parameters, variables
• remove useless variable initialisation
• remove useless Casting
• tighten visibility (public => private)
• move tests code to a separate code tree
• modernize (Java1.4 => Java5)

Second: amongst the hundreds of inspections rules offered by IDEA, a few dozens will spot oddities and probable bugs in the code (like modifying the contents of a collection passed as parameter, etc..). In those "hot" locations, I add a "todo: check", or "todo: modernize" tag, for later review.

Code clarifying : I examine the code structure, starting with the 2-mile high view of the project, and going down. Along the way, I would perform :

• rename : (package, class, method, parameter
• move : package, classes, methods, ...
• extract/inline method
• introduce variable

Note: As this has to be fast, I only "cure" the worst problems. I tag the others for later reviews: "to optimize", "to betterize", "to fix", "danger", etc..