code: @Override
      public void notifyCollided(Collidable collidable, Collision collision)
      {
          if (collidable.hasFeature(Selectable.class))
          {
              final Selectable selectable = collidable.getFeature(Selectable.class);
              selectable.onSelection(true);
              selected.add(selectable);
          }
      }
docs: /*
  CollidableListener