import java.util.HashMap;

/**
 * This interface provides the means for an implementing class to be
 * notified of room changes that occur in the MobileClient class.  When
 * a room change occurs within the MobileClient class, the
 * LocationTracker interface's roomChanged() method is called in order
 * to notify application classes that implement the LocationTracker
 * interface.
 * <p>
 * Any Java class that creates a MobileClient object needs to implement
 * the LocationTracker interface so that the MobileClient class can
 * notify the Java class of any room changes that occur.
 *
 * @author Tony Offer
 * @author Chris Palistrant
 * @version 1.0
 */
public interface LocationTracker {
    
    /**
     * This method is called by the MobileClient class when a change in
     * room location occurs.  A HashMap describing the room distribution
     * is passed into this method so that any class implementing the
     * LocationTracker interface can interpret the room change
     * appropriately.  The HashMap stores the relative magnitude of room
     * messages for wihch ultrasound has been detected.  Higher
     * magnitudes represent a greater likelihood of being in that room.
     * Thus, the HashMap represents a probability distribution for room
     * location.
     *
     * @param distribution    Collection that maps room strings to a
     *                        relative magnitude.
     */
    void roomChanged(HashMap distribution);
}