From b03b89f316acdb592fd9c0cfa01a757c4139e88f Mon Sep 17 00:00:00 2001
From: paulusja <jan.paulus1@gmx.de>
Date: Thu, 28 May 2026 16:51:53 +0200
Subject: [PATCH] Add design pattern solutions.

---
 uebungen.ipynb | 97 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 92 insertions(+), 5 deletions(-)

diff --git a/uebungen.ipynb b/uebungen.ipynb
index 528143e..08fb54c 100644
--- a/uebungen.ipynb
+++ b/uebungen.ipynb
@@ -1816,6 +1816,13 @@
     "# Erweitern Sie die Klasse Database\n",
     "\n",
     "class Database:\n",
+    "    __my_obj = None\n",
+    "\n",
+    "    def __new__(cls):\n",
+    "        if Database.__my_obj is None:\n",
+    "            Database.__my_obj = super().__new__(cls)\n",
+    "        return Database.__my_obj\n",
+    "\n",
     "    def __init__(self):\n",
     "        self.__entries = []\n",
     "\n",
@@ -1856,7 +1863,14 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "# Fügen Sie hier Ihren Code für die Quadrat-Klasse ein."
+    "# Fügen Sie hier Ihren Code für die Quadrat-Klasse ein.\n",
+    "\n",
+    "class Quadrat:\n",
+    "    def __init__(self, seitenlaenge):\n",
+    "        self.__seitenlaenge = seitenlaenge\n",
+    "\n",
+    "    def seitenlaenge(self):\n",
+    "        return self.__seitenlaenge"
    ]
   },
   {
@@ -1875,6 +1889,36 @@
    "outputs": [],
    "source": [
     "# Fügen Sie hier Ihren Code für die RechteckAdapter-Klasse ein.\n",
+    "class Rechteck:\n",
+    "    def seite1(self):\n",
+    "        pass\n",
+    "\n",
+    "    def seite2(self):\n",
+    "        pass\n",
+    "\n",
+    "    def umfang(self):\n",
+    "        pass\n",
+    "\n",
+    "    def flaecheninhalt(self):\n",
+    "        pass\n",
+    "\n",
+    "\n",
+    "class RechteckAdapter(Rechteck):\n",
+    "    def __init__(self, quadrat):\n",
+    "        self.__quadrat = quadrat\n",
+    "\n",
+    "    def seite1(self):\n",
+    "        return self.__quadrat.seitenlaenge()\n",
+    "\n",
+    "    def seite2(self):\n",
+    "        return self.__quadrat.seitenlaenge()\n",
+    "\n",
+    "    def umfang(self):\n",
+    "        return self.__quadrat.seitenlaenge() * 4\n",
+    "\n",
+    "    def flaecheninhalt(self):\n",
+    "        return self.__quadrat.seitenlaenge()**2\n",
+    "    \n",
     "\n",
     "def verarbeiteRechteck(rechteck):\n",
     "    print(f'Die 1. Seite des Rechtecks ist {rechteck.seite1()} Einheiten lang.')\n",
@@ -1884,7 +1928,7 @@
     "\n",
     "\n",
     "quadrat = Quadrat(4)\n",
-    "verarbeiteRechteck(quadrat) # Erstellen bzw. ergänzen Sie hier Ihr Adapter-Objekt, um es mit dem Quadrat-Objekt an die Funktion zu übergeben."
+    "verarbeiteRechteck(RechteckAdapter(quadrat)) # Erstellen bzw. ergänzen Sie hier Ihr Adapter-Objekt, um es mit dem Quadrat-Objekt an die Funktion zu übergeben."
    ]
   },
   {
@@ -1905,12 +1949,51 @@
    "source": [
     "# Fügen Sie hier Ihren Code für die Klasse EntryCounter ein.\n",
     "\n",
+    "class EntryCounter:\n",
+    "    def __init__(self, max_persons):\n",
+    "        self.__max_persons = max_persons\n",
+    "        self.__count = 0\n",
+    "        self.__lights = []\n",
+    "        self.__state = None\n",
+    "\n",
+    "    def someone_enters(self):\n",
+    "        self.__count += 1\n",
+    "        self.__update_state()\n",
+    "\n",
+    "    def someone_leaves(self):\n",
+    "        self.__count -= 1\n",
+    "        self.__update_state()\n",
+    "\n",
+    "    def get_count(self):\n",
+    "        return self.__count\n",
+    "    \n",
+    "    def register(self, light):\n",
+    "        self.__lights.append(light)\n",
+    "    \n",
+    "    def __update_state(self):\n",
+    "        state = None\n",
+    "        if self.__count + 1 < self.__max_persons:\n",
+    "            state = 'green'\n",
+    "        elif self.__count + 1 == self.__max_persons:\n",
+    "            state = 'yellow'\n",
+    "        else:\n",
+    "            state = 'red'\n",
+    "\n",
+    "        if state != self.__state:\n",
+    "            for light in self.__lights:\n",
+    "                light.update(state)\n",
+    "            self.__state = state\n",
+    "\n",
+    "\n",
     "class TrafficLight:\n",
     "    def __init__(self, status):\n",
     "        self.__status = status\n",
     "\n",
     "    def get_light_status(self):\n",
     "        return self.__status\n",
+    "    \n",
+    "    def update(self, status):\n",
+    "        self.__status = status\n",
     "\n",
     "    # Erweitern Sie hier die Klasse TrafficLight um weitere Methoden, falls notwendig."
    ]
@@ -1928,16 +2011,20 @@
     "\n",
     "entry_counter = EntryCounter(5)\n",
     "# Fügen Sie hier zusätzlichen Code für entry_counter ein, falls notwendig, und nur, wenn Sie in der Aufgabenbeschreibung dazu aufgefordert werden.\n",
+    "entry_counter.register(traffic_light1)\n",
+    "entry_counter.register(traffic_light2)\n",
     "\n",
     "for enter_or_leave in [1, 1, 1, 1, -1, 1, 1, 1, -1, -1, -1, -1]:\n",
     "    if enter_or_leave == 1:\n",
-    "        entry_counter.someoneEnters()\n",
+    "        print('Someone enters')\n",
+    "        entry_counter.someone_enters()\n",
     "    elif enter_or_leave == -1:\n",
-    "        entry_counter.someoneLeaves()\n",
+    "        print('Someone leaves')\n",
+    "        entry_counter.someone_leaves()\n",
     "    else:\n",
     "        print(f'Unrecognized code: {enter_or_leave}')\n",
     "\n",
-    "    print(f'People in the room: {entry_counter.getCount()}')\n",
+    "    print(f'People in the room: {entry_counter.get_count()}')\n",
     "    print(f'Traffic light 1: {traffic_light1.get_light_status()}')\n",
     "    print(f'Traffic light 2: {traffic_light2.get_light_status()}\\n')"
    ]