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 f开发者_StackOverflowinal 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?
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);
}
Interesting question. A more condense implementation of @ob1's suggestion:
public static void smartPrintln(String string) {
int i = new Throwable().getStackTrace().length - 1;
System.out.printf("%"+i+"s%s%n", "", string);
}
Another solution would be to "add the functionality" directly to System.out.println
calls like this:
System.setOut(new PrintStream(System.out) {
public void println(String x) {
printf("%"+(new Throwable().getStackTrace().length - 1)+"s", "");
super.println(x);
}
});
After this point, all calls to System.out.println(String)
will be processed by our "filtering" PrintStream implementation.
Use the Logger API or anyother third party API.
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