//
// utility class to display info about current thread, or all
//      threads in current thread group.
// see main program for example of use.  to use methods
//      elsewhere, reference as, e.g., ShowThreads.show("message").
//
class ShowThreads {

        // writes to standard output info about current thread, plus 
        //      a user-supplied identifying message.
        static void show(String msg) {
                System.out.println(msg + ":  current thread = " +
                        Thread.currentThread()) ;
        }

        // writes to standard output info about all active threads, plus
        //      a user-supplied identifying message.
        static void showAll(String msg) {
                System.out.println(msg + ":  active threads = ") ;
                Thread.currentThread().getThreadGroup().list() ;
        }

        // first delays, then invokes showAll above (useful, e.g.,
        //      when starting an AWT program, to give the runtime
        //      system time to start the AWT threads).
        static void showAll(String msg, int seconds) {
                try {
                        Thread.currentThread().sleep(
                                (long) (1000 * seconds)) ;
                } catch (InterruptedException e) { }
                showAll(msg) ;
        }

        //
        // no command-line arguments.
        //
        public static void main(String[] args) {
                show("in main") ;
                showAll("in main") ;
                showAll("in main after 10 secs", 10) ;

                Thread t1 = new Thread() ;
                showAll("in main after creating new thread") ;
        }
}