// Robot uses the built-in Color class in java.awt.Color.  (see Java API)
import java.awt.Color; 

/**   FeelingRobot is a BouncingRobot except that it uses sensors
 *    to detect the wall before actually hitting it.  (Hopefully,
 *    this will protect the stepper from stress.)
 */
public class FeelingRobot extends BouncingRobot {

   // fields

   //    new parts
   protected Sensor front,    // front sensor
                    back;     // back sensor

   // constructor

   /**   FeelingRobot now also accepts Sensor objects for the
    *    whiskers and tail, which are the front and back 
    *    sensors, respectively.
    */
   public FeelingRobot( Stepper s, Color c, 
                        Sensor whiskers, Sensor tail ) {
      // first call the superclass's constructor
      // (note: Java requires that the super constructor, if called, 
      // *must* be the first line in the constructor!)
      super( s, c );

      // then do the new stuff
      this.front = whiskers;
      this.back = tail;
   }

   /**   This overrides BouncingRobots act().  Here, right before
    *    we try to move, we check the sensors and adjust the direction
    *    accordingly if the sensors sense anything.
    */
   public void act()
   {
      // check the sensors
      if ( front.sensesSomething() ) {
         // if front sensor hits a wall or something, 
         // then we decide to move backward
         movingForward = false;
      } else if ( back.sensesSomething() ) {
         // if back sensor hits something,
         // then we decide to move forward
         movingForward = true;
      }

      // Note: if sensors don't sense anything, then movingForward
      // is not changed.

      // Now call BouncingRobot's act() method
      super.act();
   }


}