Method addLayer

src/main/java/mudmap2/backend/World.java:212–222

Adds or replaces a layer @param layer

(Layer layer)

     * @param layer
     */
    public void addLayer(Layer layer){ // TODO: throw Exception if layer exists
        if(layer == null){
            throw new NullPointerException();
        }

        if(!layers.containsKey(layer.getId()))
            layers.put(layer.getId(), layer);

        addChangeListener(layer);
        callListeners(layer);
    }
    
    /**
     * Deletes a layer and all places on it