Flyweight example

Author: MichalKorzycki

18_Wstep_do_obiektowosci/flyweight.py

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+from weakref import WeakValueDictionary
+
+
+class flyweight:
+    def __init__(self, cls):
+        self._cls = cls
+        self._instances = WeakValueDictionary()
+
+    def __call__(self, *args, **kargs):
+        return self._instances.setdefault(
+            (args, tuple(kargs.items())),
+            self._cls(*args, **kargs))
+
+
+@flyweight
+class Card:
+    values = ('2', '3', '4', '5', '6', '7', '8', '9', '10', 'J', 'Q', 'K', 'A')
+    suits = ('clubs', 'diamonds', 'hearts', 'spades')
+
+    def __init__(self, value='A', suit='spade'):
+        self.value, self.suit = value, suit
+        print(f"In init; value is {value}; suit is {suit}")
+
+    def __repr__(self):
+        return "Card('%s','%s')" % (self.value, self.suit)
+
+    def __eq__(self, card):
+        return self.value == card.value and self.suit == card.suit
+
+    def czy_bije(self, other):
+        if self.suit == other.suit:
+            if self.values.index(self.value) > self.values.index(other.value):
+                return True
+        return False
+
+    def __gt__(self, n):
+        return self.czy_bije(n)
+
+    def __lt__(self, card):
+        return card.czy_bije(self)
+
+
+krol_karo1 = Card('K', 'diamonds')
+krol_karo2 = Card('K', 'diamonds')
+
+krol_karo1 is krol_karo2