The GPSSubject Interface (v1.0)

A GPSSubject is an object that informs GPSObserver objects of GPS "sentences" (i.e., NMEA sentences).

This interface has the following method(s):

    /**
     * Add a GPSObserver to the collection of observers
     *
     * @param observer The GPSObserver to add
     */
    public abstract void addGPSObserver(GPSObserver observer);

    /**
     * Notify all current observers of GPS data
     *
     * @param data  The String containing the GPS data
     */
    public abstract void notifyGPSObservers(String data);

    /**
     * Remove a GPSObserver from the collection of observers
     *
     * @param observer The GPSObserver to remove
     */
    public abstract void removeGPSObserver(GPSObserver observer);

    /**
     * Start "publishing" GPS data
     */
    public abstract void start();