Traffic Light.ipynb

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   "source": [
    "# Traffic Light\n",
    "\n",
    "This is an exercise for the lecture and not part of the mandatory preparation material. "
   ]
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    "import ipywidgets as widgets\n",
    "from IPython.display import display\n",
    "from stmpy import Machine, Driver\n",
    "\n",
    "class TrafficLight:\n",
    "    \n",
    "    def load_images(self):\n",
    "        self.red_on = open(\"images/red_on.png\", \"rb\").read()\n",
    "        self.red_off = open(\"images/red_off.png\", \"rb\").read()\n",
    "        self.yellow_on = open(\"images/yellow_on.png\", \"rb\").read()\n",
    "        self.yellow_off = open(\"images/yellow_off.png\", \"rb\").read()\n",
    "        self.green_on = open(\"images/green_on.png\", \"rb\").read()\n",
    "        self.green_off = open(\"images/green_off.png\", \"rb\").read()\n",
    "        \n",
    "    def on_button_switch(self, b):\n",
    "        self.stm.send('switch')\n",
    "        \n",
    "    def on_button_terminate(self, b):\n",
    "        self.stm.driver.stop()\n",
    "    \n",
    "    def display(self):\n",
    "        self.button_switch = widgets.Button(description=\"Switch\")\n",
    "        self.button_switch.on_click(self.on_button_switch)\n",
    "        self.button_terminate = widgets.Button(description=\"Terminate\")\n",
    "        self.button_terminate.on_click(self.on_button_terminate)\n",
    "        self.red = widgets.Image(value=self.red_off, format='png', width=50, height=50)\n",
    "        self.yellow = widgets.Image(value=self.yellow_off, format='png', width=50, height=50)\n",
    "        self.green = widgets.Image(value=self.green_off, format='png', width=50, height=50)\n",
    "        display(self.red, self.yellow, self.green, self.button_switch, self.button_terminate)\n",
    "        \n",
    "    def __init__(self):\n",
    "        self.load_images()\n",
    "        self.display()\n",
    "        \n",
    "    def turn_red_on(self):\n",
    "        self.red.set_trait(name='value', value=self.red_on)\n",
    "        \n",
    "    def turn_red_off(self):\n",
    "        self.red.set_trait(name='value', value=self.red_off)\n",
    "        \n",
    "    def turn_yellow_on(self):\n",
    "        self.yellow.set_trait(name='value', value=self.yellow_on)\n",
    "        \n",
    "    def turn_yellow_off(self):\n",
    "        self.yellow.set_trait(name='value', value=self.yellow_off)\n",
    "        \n",
    "    def turn_green_on(self):\n",
    "        self.green.set_trait(name='value', value=self.green_on)\n",
    "        \n",
    "    def turn_green_off(self):\n",
    "        self.green.set_trait(name='value', value=self.green_off)"
   ]
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  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import logging\n",
    "\n",
    "traffic = TrafficLight()\n",
    "\n",
    "t0 = {'source': 'initial',\n",
    "      'target': 'off'}\n",
    "\n",
    "t1 = {'trigger':'switch',\n",
    "      'source':'off',\n",
    "      'target':'red',\n",
    "      'effect':'turn_red_on'\n",
    "}\n",
    "t2 = {'trigger':'switch', \n",
    "      'source':'red', \n",
    "      'target':'red_yellow', \n",
    "      'effect':'turn_yellow_on'\n",
    "}\n",
    "t3 = {'trigger':'switch', \n",
    "      'source':'red_yellow', \n",
    "      'target':'green', \n",
    "      'effect':'turn_red_off; turn_yellow_off; turn_green_on'\n",
    "}\n",
    "t4 = {'trigger':'switch', \n",
    "      'source':'green', \n",
    "      'target':'yellow', \n",
    "      'effect':'turn_green_off; turn_yellow_on'\n",
    "}\n",
    "t5 = {'trigger':'switch', \n",
    "      'source':'yellow', \n",
    "      'target':'red', \n",
    "      'effect':'turn_yellow_off; turn_red_on'\n",
    "}\n",
    "stm_traffic = Machine(name='stm_traffic', transitions=[t0, t1, t2, t3, t4, t5], obj=traffic)\n",
    "traffic.stm = stm_traffic\n",
    "\n",
    "logger = logging.getLogger('stmpy.Driver')\n",
    "logger.setLevel(logging.INFO)\n",
    "ch = logging.StreamHandler()\n",
    "ch.setLevel(logging.INFO)\n",
    "formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')\n",
    "ch.setFormatter(formatter)\n",
    "logger.addHandler(ch)\n",
    "\n",
    "logger = logging.getLogger('stmpy.Machine')\n",
    "logger.setLevel(logging.INFO)\n",
    "ch = logging.StreamHandler()\n",
    "ch.setLevel(logging.INFO)\n",
    "formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')\n",
    "ch.setFormatter(formatter)\n",
    "logger.addHandler(ch)\n",
    "\n",
    "%config Application.log_level=\"INFO\"\n",
    "    \n",
    "\n",
    "driver = Driver()\n",
    "driver.add_machine(stm_traffic)\n",
    "driver.start()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Task 1: Create a Diagram\n",
    "\n",
    "Create a state machine diagram of the traffic light above.\n",
    "\n",
    "# Task 2: Use Entry and Exit Actions\n",
    "\n",
    "Create another version of the state machine that uses states with entry and exit actions."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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