Question

I am using System.out.println in my code to track the execution of a program and get some useful output. This creates results like this in the console:

Main function. Program starts.
Method getArea. Getting values
Method getSide. Side is 6
Method getArea. First value is 6
Method getSide. Side is 8
Method getArea. Second value is 8
Method getArea. Area is 48
Main function. The final area is 48

I would like to create tha method, which adds a space in front of the output every time the code goes deeper in the method call stack. For example, the same code but instead of using System.out.println, now with Misc.smartPrintln:

Main function. Program starts.
 Method getArea. Getting values
  Method getSide. Side is 6
 Method getArea. First value is 6
  Method getSide. Side is 8
 Method getArea. Second value is 8
 Method getArea. Area is 48
Main function. The final area is 48

The method would have this definition:

public static void smartPrintln(String string);

I don’t know how to implement this functionality. Any ideas how to solve this? And, could the use of a logger offer this functionality?

Answer 1

Create a temporary Throwable object.
Use its getStackTrace() method to analyze the stack and determine the level.
e.g.

public static void smartPrintln(String string) {
    Throwable t = new Throwable();
    StackTraceElement[] stackElements = t.getStackTrace();
    int level = stackElements.length - 1; // don't forget our function adds a level
    for (int i = 0; i < level; i++) {
        System.out.print(' '); // could probably make this more efficient
    }
    System.out.println(string);
}