import java.io.*;

/** Taken from Core Web Programming from 
 *  Prentice Hall and Sun Microsystems Press,
 *  http://www.corewebprogramming.com/.
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted. 
 */

public class NegativeLengthException extends Exception {

  /** Test NegativeLengthException */

  public static void main(String[] args) {
    try {
      int lineLength = readLength();
      for(int i=0; i<lineLength; i++) {
        System.out.print("*");
      }
      System.out.println();
    } catch (NegativeLengthException nle) {
      System.out.println("NegativeLengthException: " +
                         nle.getMessage());
    }
  }

  public NegativeLengthException() {
    super("Negative dimensions not permitted.");
  }

  public NegativeLengthException(String message) {
    super(message);
  }

  // readLength catches IOExceptions locally but lets the
  // calling method handle NegativeLengthExceptions.
  private static int readLength() throws NegativeLengthException {
    BufferedReader in = new BufferedReader(
                          new InputStreamReader(System.in));
    System.out.print("Enter length: ");
    System.out.flush();
    int len = 0;
    try {
      String line = in.readLine();
      len = Integer.parseInt(line);
      if (len < 0) {
        throw new NegativeLengthException();
      }
    } catch (IOException ioe) {
      System.out.println("Problem reading from keyboard");
    }
    return(len);
  }
}