Question in Overriding

Question

Hi,
In the following example code snippets
class Base
     private static Common com = new Common();
     public static void write(String data)
          com.print("Base "+data);
class Common
    public void print(String data)
         System.out.println(data);
class Sub extends Common
     public void print(String data)
          System.out.println("sub "+data);
public class SomeOther
      public static void main(String args[])
           Base.write("hello world");
}In my project Base's write method is called from 50 different files a lot of times. I can only change Sub class, so that when ever Base's write method is called, the control should go to Sub's print method. Reason is, I have to do some validation when ever a line is wriiten. Since I can not change the base class by any means, is there any way to include the validation code in Sub class and be called whenever Base's method is called?
Thank you.
Raj.

Answer 1

Thanks guys, for your replies.
Well, The Base�s method actullay uses PrintWriter�s println method to redirect all the log data to a file. This Base class is only available to us in a jar file. We are not allowed to change it.
The task I am trying to do is, when ever a line is written to the log file, I have to check the current timestamp against the timestamp written in the first line of the file. And have to do some tasks accroding to that.
I tried a FileListener interface to listen to the file . But this took most of the CPU since my application has already 30 threads running concurrently. I am almost stuck in this for past two days.Can you suggest any other way of doing this?
Thanks
Raj