/**
   Demonstrates exception propagation.
  
   @author John Lewis and William Loftus
   @version 1.1
   @author Franck van Breugel
   @version 1.2    May 6, 2002
*/
public class ExceptionScope
{
    /** Catches and handles the exception that is thrown in level3. */
    public void level1()
    {
        System.out.println("Level 1 beginning.");

        try
        {
            level2();
        }
        catch (ArithmeticException e)
        {
            System.out.println ();
            System.out.println ("The exception message is: " + e.getMessage());
            System.out.println ();
            System.out.println ("The call stack trace:");
            e.printStackTrace();
            System.out.println ();
        }

        System.out.println("Level 1 ending.");
    }

    /**
       Serves as an intermediate level.  The exception propagates
       through this method back to level1.
    */
    public void level2()
    {
        System.out.println("Level 2 beginning.");
        level3();
        System.out.println("Level 2 ending.");
     }

    /**
       Performs a calculation to produce an exception.  It is not
       caught and handled at this level.
    */
    public void level3()
    {
        int numerator = 1;
        int denominator = 0;

        System.out.println("Level 3 beginning.");
        int result = numerator / denominator;
        System.out.println("Level 3 ending.");
    }
}