Method breadthSearch

src/main/java/mudmap2/backend/World.java:567–593

does a breadth search @param start start place @param end end place @return end place or null. Following the predecessors of this path leads to the start place

(Place start, Place end)

     * to the start place
     */
    @Override
    public Place breadthSearch(Place start, Place end) {
        for(Layer layer: getLayers()){
            for(Place place: layer.getPlaces()){
                place.breadthSearchReset();
            }
        }
        start.getBreadthSearchData().marked = true;

        LinkedList<Place> queue = new LinkedList<>();
        queue.add(start);

        while(!queue.isEmpty()){
            Place v = queue.pollFirst();
            if(v == end) return v;

            for(Path pa: v.getPaths()){
                Place vi = pa.getOtherPlace(v);
                if(!vi.getBreadthSearchData().marked && vi != v && !pa.getExit(v).equals("-")){
                    vi.getBreadthSearchData().marked = true;
                    vi.getBreadthSearchData().predecessor = v;
                    queue.addLast(vi);
                }
            }
        }
        return null;
    }

    // --------- listeners -----------------------------------------------------
    /**