protected final void change(Entity e)
    {
        boolean contains = (systemBit & e.getSystemBits()) == systemBit;
        boolean interest = (typeFlags & e.getTypeBits()) == typeFlags;
        
        if (interest && !contains && typeFlags > 0)
        {
            actives.add(e);
            e.addSystemBit(systemBit);
            added(e);
        }
        else if (!interest && contains && typeFlags > 0)
        {
            remove(e);
        }
    }