@Nullable
    public Waypoint getWaypointByPrefix(final String prefix) {
        for (final Waypoint waypoint : waypoints) {
            if (waypoint.getPrefix().equals(prefix)) {
                return waypoint;
            }
        }
        return null;
    }
Lookup a waypoint by its prefix.

@param prefix the prefix of the waypoint to look for
@return waypoint or {@code null}
main/src/main/java/cgeo/geocaching/models/Geocache.java