Question

Before I reinvent the wheel – I want to be able to insert debugging traces in my code, such as say("We are here.");, without defining static void say() in every class. It needs to do System.out.println(s), and to be globally switched on or off (doSay(false)), and I’d also like it to be able to identify the class from which it’s being invoked (as described here). For example:

MyClass: We are here.

Does Java already have such a tool?

Answer 1

I didn’t know about static import! I combined ideas from @ninetwozero, @karl, and @erickson to create this:

package myPkg;
public class CLHUtilities {

    private static boolean saying = false;
    public static void tracing(boolean b) {
        saying = b;
    }

    /*
     * Technique taken from:
     * http://stackoverflow.com/questions/282977/which-class-invoked-my-static-method
     */
    public static void say(String s) {
        if (saying) {
            Throwable t = new Throwable();
            StackTraceElement[] trace = t.getStackTrace();
            String className = trace[1].getClassName();
            String whoCalledMe = null;
            try {
                whoCalledMe = Class.forName(className).getSimpleName();
            } catch (Exception e) {
            }
            System.out.println(whoCalledMe + ": " + s);
        }

    }
}

which can be used simply as:

import static myPkg.CLHUtilities.*;
 :
tracing(true);
 :
say("We are here.");

Which suits my needs perfectly.