How to comment out calls to a specific API in Java source code

Question

I want to comment out all calls to an API (java.util.Logging, in my case) in my codebase. Is there a good library to accomplish this easily? I tried Eclipse ASTParser, but that is tied to Eclipse. I am now struggling with PMD's parser. I haven't yet looked at it, but can Jackpot do this? Any other suggestions?

Answer 1

sed? Just substitute with a commented line. You'll need to think about the match regex to catch multiline calls.

Answer 2

I know this isn't what you asked for, but I just want to draw your attention to the fact that you can turn logging OFF in your configuration file.

Answer 3

You can use slf4j's jul-to-slf4j module to redirect all java.util.logging calls into slf4j, and then you can choose the slf4j-nop module to ignore all the logging statements.

Will this do, or do you REALLY need to get rid of these source lines?

Answer 4

using a tool to comment out or remove all of the logging code might be a bad idea.

There might be side effect code that you don't notice:

while ( x > 5)
{
    // some code here
    Logger.global.finest( "X is now bigger: " + (x++) );
}

thats a real obvious example, but it could be very subtle with a method call or something inside the logger call.

It is probably safer to turn off the logging output, or go through the whole thing manually...

Answer 5

If you're looking to avoid evaluation of arguments, as you say in your comments, then I assume you have calls like:

logger.log("Expensive toString() operation on " + this);

which you want to disable ?

If that's the case, and it's scattered through your code, I'd use something like AspectJ to surround all instances of the above with:

if (loggingEnabled) {
   ...
}

and set the loggingEnabled flag to false.

Answer 6

If you wanted to comment out this:

Log.doLog("Here is a" /* With a block comment to make it hard */
    + " multiline log statement"
    ); doSomethingEssential();

then you'd have a trickier time of it because you'd need to parse the code to some extend to know where to put the comments. I.e. you want to be able to do this:

// Log.doLog("Here is a" /* With a block comment to make it hard */
//     + " multiline log statement"
//     ); // Line break inserted here
doSomethingEssential();

It's much more trivial to do this instead:

if (false) Log.doLog("Here is a" /* With a block comment to make it hard */
    + " multiline log statement"
    );

The 'if false' part ends up being optimised out by the compiler and the Log statement won't make it to the final .class file.

That way all you need is a search/replace step in your build script that replaces all occurences of

"Log.doLog("

with either

"if (false) Log.doLog(" or
"if (true) Log.doLog("

without resorting to tricky parsing of the code.