chapter 9

Author: rebuild-123

README.md

@@ -10,6 +10,7 @@
 [chapter 7(facade)](https://github.com/rebuild-123/Python-Head-First-Design-Patterns/tree/main/facade/hometheater) 
 [chapter 8(templatemethod)](https://github.com/rebuild-123/Python-Head-First-Design-Patterns/tree/main/templatemethod) (applet and frame have no translation.) 
 [chapter 9(iterator)](https://github.com/rebuild-123/Python-Head-First-Design-Patterns/tree/main/iterator) 
+[chapter 9(composite)](https://github.com/rebuild-123/Python-Head-First-Design-Patterns/tree/main/composite) 
 ## Introduction 
 1. Translated from [Head-First-Design-Patterns](https://github.com/bethrobson/Head-First-Design-Patterns) (java) 
 2. What are the differences between other Python version Head-First-Design-Patterns and ours? 

composite/menu/Menu.py

@@ -0,0 +1,46 @@
+from typing import Iterator, List
+
+from MenuComponent import MenuComponent
+
+
+class Menu(MenuComponent):
+ iterator: Iterator[MenuComponent] = None
+ menuComponents: List[MenuComponent]
+ name: str
+ description: str
+ 
+ def __init__(self, name: str, description: str):
+ self.name = name
+ self.description = description
+ self.menuComponents = []
+ 
+ def add(self, menuComponent: MenuComponent) -> None:
+ self.menuComponents.append(menuComponent)
+ 
+ def remove(self, menuComponent: MenuComponent) -> None:
+ self.menuComponents.remove(menuComponent)
+ 
+ def getChild(self, i: int) -> MenuComponent:
+ return self.menuComponents[i]
+ 
+ def getName(self) -> str:
+ return self.name
+ 
+ def getDescription(self) -> str:
+ return self.description
+ 
+ def createIterator(self) -> Iterator[MenuComponent]:
+ if self.iterator == None:
+ self.iterator = CompositeIterator(iter(self.menuComponents))
+ return self.iterator
+ 
+ def print(self) -> None:
+ print(f'\n{self.getName()}', end="")
+ print(f", {self.getDescription()}")
+ print("---------------------")
+ 
+ iterator: Iterator[MenuComponent] = iter(self.menuComponents)
+ menuComponent: MenuComponent = next(iterator, None)
+ while menuComponent != None:
+ menuComponent.print()
+ menuComponent: MenuComponent = next(iterator, None)

composite/menu/MenuComponent.py

@@ -0,0 +1,27 @@
+from __future__ import annotations
+from abc import ABC, abstractmethod
+from typing import Iterator
+
+
+class UnsupportedOperationException(Exception): pass
+
+class MenuComponent(ABC):
+ 
+ def add(self, menuComponent: MenuComponent) -> None:
+ raise UnsupportedOperationException
+ def remove(self, menuComponent: MenuComponent) -> None:
+ raise UnsupportedOperationException
+ def getChild(self, i: int) -> MenuComponent:
+ raise UnsupportedOperationException
+ 
+ def getName(self) -> str:
+ raise UnsupportedOperationException
+ def getDescription(self) -> str:
+ raise UnsupportedOperationException
+ def getPrice(self) -> float:
+ raise UnsupportedOperationException
+ def isVegetarian(self) -> bool:
+ raise UnsupportedOperationException
+ 
+ def print(self) -> None:
+ raise UnsupportedOperationException

composite/menu/MenuItem.py

@@ -0,0 +1,38 @@
+from typing import Iterator
+
+from MenuComponent import MenuComponent
+
+
+class MenuItem:
+ name: str
+ description: str
+ vegetarian: bool
+ price: float
+ 
+ def __init__(self, name: str, description: str, vegetarian: bool, price: float):
+ self.name = name
+ self.description = description
+ self.vegetarian = vegetarian
+ self.price = price
+ 
+ def getName(self) -> str:
+ return self.name
+ 
+ def getDescription(self) -> str:
+ return self.description
+ 
+ def getPrice(self) -> float:
+ return self.price
+ 
+ def isVegetarian(self) -> bool:
+ return self.vegetarian
+ 
+ def createIterator(self) -> Iterator[MenuComponent]:
+ return NullIterator()
+ 
+ def print(self) -> None:
+ print(f" {self.getName()}", end="")
+ if self.isVegetarian():
+ print(f"(v)", end="")
+ print(f", {self.getPrice()}")
+ print(f" -- {self.getDescription()}")

composite/menu/MenuTestDrive.py

@@ -0,0 +1,54 @@
+from Menu import Menu
+from MenuComponent import MenuComponent
+from MenuItem import MenuItem
+from Waitress import Waitress
+
+
+class MenuTestDrive:
+ @staticmethod
+ def main(*args):
+ pancakeHouseMenu: MenuComponent = Menu("PANCAKE HOUSE MENU", "Breakfast")
+ dinerMenu: MenuComponent = Menu("DINER MENU", "Lunch")
+ cafeMenu: MenuComponent = Menu("CAFE MENU", "Dinner")
+ dessertMenu: MenuComponent = Menu("DESSERT MENU", "Dessert of course!")
+ coffeeMenu: MenuComponent = Menu("COFFEE MENU", "Stuff to go with your afternoon coffee")
+ 
+ allMenus: MenuComponent = Menu("ALL MENUS", "All menus combined")
+ 
+ allMenus.add(pancakeHouseMenu)
+ allMenus.add(dinerMenu)
+ allMenus.add(cafeMenu)
+ 
+ pancakeHouseMenu.add(MenuItem( "K&B's Pancake Breakfast", "Pancakes with scrambled eggs and toast", True, 2.99))
+ pancakeHouseMenu.add(MenuItem( "Regular Pancake Breakfast", "Pancakes with fried eggs, sausage", False, 2.99))
+ pancakeHouseMenu.add(MenuItem( "Blueberry Pancakes", "Pancakes made with fresh blueberries and blueberry syrup", True, 3.49))
+ pancakeHouseMenu.add(MenuItem( "Waffles", "Waffles with your choice of blueberries or strawberries", True, 3.59))
+ 
+ dinerMenu.add(MenuItem( "Vegetarian BLT", "(Fakin') Bacon with lettuce & tomato on whole wheat", True, 2.99))
+ dinerMenu.add(MenuItem( "BLT", "Bacon with lettuce & tomato on whole wheat", False, 2.99))
+ dinerMenu.add(MenuItem( "Soup of the day", "A bowl of the soup of the day, with a side of potato salad", False, 3.29))
+ dinerMenu.add(MenuItem( "Hot Dog", "A hot dog, with saurkraut, relish, onions, topped with cheese", False, 3.05))
+ dinerMenu.add(MenuItem( "Steamed Veggies and Brown Rice", "A medly of steamed vegetables over brown rice", True, 3.99))
+ dinerMenu.add(MenuItem( "Pasta", "Spaghetti with marinara sauce, and a slice of sourdough bread", True, 3.89))
+ dinerMenu.add(dessertMenu)
+ 
+ dessertMenu.add(MenuItem( "Apple Pie", "Apple pie with a flakey crust, topped with vanilla icecream", True, 1.59))
+ dessertMenu.add(MenuItem( "Cheesecake", "Creamy New York cheesecake, with a chocolate graham crust", True, 1.99))
+ dessertMenu.add(MenuItem( "Sorbet", "A scoop of raspberry and a scoop of lime", True, 1.89))
+ 
+ cafeMenu.add(MenuItem( "Veggie Burger and Air Fries", "Veggie burger on a whole wheat bun, lettuce, tomato, and fries", True, 3.99))
+ cafeMenu.add(MenuItem( "Soup of the day", "A cup of the soup of the day, with a side salad", False, 3.69))
+ cafeMenu.add(MenuItem( "Burrito", "A large burrito, with whole pinto beans, salsa, guacamole", True, 4.29))
+ 
+ cafeMenu.add(coffeeMenu)
+ 
+ coffeeMenu.add(MenuItem("Coffee Cake", "Crumbly cake topped with cinnamon and walnuts", True, 1.59))
+ coffeeMenu.add(MenuItem("Bagel", "Flavors include sesame, poppyseed, cinnamon raisin, pumpkin", False, 0.69))
+ coffeeMenu.add(MenuItem("Biscotti", "Three almond or hazelnut biscotti cookies", True, 0.89))
+ 
+ waitress: Waitress = Waitress(allMenus)
+ 
+ waitress.printMenu() # book's example
+ 
+if __name__ == "__main__":
+ MenuTestDrive.main()

composite/menu/Waitress.py

@@ -0,0 +1,15 @@
+from typing import Iterator
+
+from MenuComponent import MenuComponent
+
+
+class UnsupportedOperationException(Exception): pass
+
+class Waitress:
+ allMenus: MenuComponent
+ 
+ def __init__(self, allMenus: MenuComponent):
+ self.allMenus = allMenus
+ 
+ def printMenu(self) -> None:
+ self.allMenus.print()

composite/menuiterator/CompositeIterator.py

@@ -0,0 +1,36 @@
+from collections import deque
+from typing import Deque, Iterator, List
+
+from MenuComponent import MenuComponent
+
+
+class CompositeIterator(Iterator[MenuComponent]):
+ stack: Deque[Iterator[MenuComponent]]
+ 
+ def __init__(self, iterator: Iterator[MenuComponent]):
+ self.stack = deque()
+ self.stack.append(iterator)
+ 
+ def __iter__(self):
+ return self
+ 
+ # next
+ def __next__(self) -> MenuComponent:
+ if self.hasNext():
+ iterator: Iterator[MenuComponent] = self.stack[-1] if len(self.stack) != 0 else None
+ component: MenuComponent = next(iterator)
+ self.stack.append(component.createIterator())
+ return component
+ else:
+ raise StopIteration
+ 
+ def hasNext(self) -> bool:
+ if len(self.stack) == 0:
+ return False
+ else:
+ iterator: Iterator[MenuComponent] = self.stack[-1] if len(self.stack) != 0 else None
+ if not iterator.hasNext():
+ self.stack.pop()
+ return self.hasNext()
+ else:
+ return True

composite/menuiterator/Menu.py

@@ -0,0 +1,71 @@
+from collections import UserList
+from typing import Iterator, List
+
+from CompositeIterator import CompositeIterator
+from MenuComponent import MenuComponent
+
+
+class My_List(UserList): 
+ def __init__(self, data):
+ super().__init__(data)
+ self.position = 0
+ 
+ def __iter__(self):
+ return self
+ 
+ def __next__(self):
+ if self.hasNext():
+ num = self.data[self.position]
+ self.position += 1
+ return num
+ else:
+ raise StopIteration
+ 
+ def hasNext(self):
+ if self.position >= len(self.data):
+ self.position = 0
+ return False
+ else:
+ return True
+
+class Menu(MenuComponent):
+ iterator: Iterator[MenuComponent] = None
+ menuComponents: List[MenuComponent]
+ name: str
+ description: str
+ 
+ def __init__(self, name: str, description: str):
+ self.name = name
+ self.description = description
+ self.menuComponents = My_List([])
+ 
+ def add(self, menuComponent: MenuComponent) -> None:
+ self.menuComponents.append(menuComponent)
+ 
+ def remove(self, menuComponent: MenuComponent) -> None:
+ self.menuComponents.remove(menuComponent)
+ 
+ def getChild(self, i: int) -> MenuComponent:
+ return self.menuComponents[i]
+ 
+ def getName(self) -> str:
+ return self.name
+ 
+ def getDescription(self) -> str:
+ return self.description
+ 
+ def createIterator(self) -> Iterator[MenuComponent]:
+ if self.iterator == None:
+ self.iterator = CompositeIterator(iter(self.menuComponents))
+ return self.iterator
+ 
+ def print(self) -> None:
+ print(f'\n{self.getName()}', end="")
+ print(f", {self.getDescription()}")
+ print("---------------------")
+ 
+ iterator: Iterator[MenuComponent] = iter(self.menuComponents)
+ menuComponent: MenuComponent = next(iterator, None)
+ while menuComponent != None:
+ menuComponent.print()
+ menuComponent: MenuComponent = next(iterator, None)

composite/menuiterator/MenuComponent.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+from abc import ABC, abstractmethod
+from typing import Iterator
+
+
+class UnsupportedOperationException(Exception): pass
+
+class MenuComponent(ABC):
+ 
+ def add(self, menuComponent: MenuComponent) -> None:
+ raise UnsupportedOperationException
+ def remove(self, menuComponent: MenuComponent) -> None:
+ raise UnsupportedOperationException
+ def getChild(self, i: int) -> MenuComponent:
+ raise UnsupportedOperationException
+ def getName(self) -> str:
+ raise UnsupportedOperationException
+ def getDescription(self) -> str:
+ raise UnsupportedOperationException
+ def getPrice(self) -> float:
+ raise UnsupportedOperationException
+ def isVegetarian(self) -> bool:
+ raise UnsupportedOperationException
+ @abstractmethod
+ def createIterator(self) -> Iterator[MenuComponent]:
+ raise NotImplementedError
+ def print(self) -> None:
+ raise UnsupportedOperationException

composite/menuiterator/MenuItem.py

@@ -0,0 +1,40 @@
+from typing import Iterator
+
+from MenuComponent import MenuComponent
+from NullIterator import NullIterator
+
+
+class MenuItem:
+ 
+ name: str
+ description: str
+ vegetarian: bool
+ price: float
+ 
+ def __init__(self, name: str, description: str, vegetarian: bool, price: float):
+ self.name = name
+ self.description = description
+ self.vegetarian = vegetarian
+ self.price = price
+ 
+ def getName(self) -> str:
+ return self.name
+ 
+ def getDescription(self) -> str:
+ return self.description
+ 
+ def getPrice(self) -> float:
+ return self.price
+ 
+ def isVegetarian(self) -> bool:
+ return self.vegetarian
+ 
+ def createIterator(self) -> Iterator[MenuComponent]:
+ return NullIterator()
+ 
+ def print(self) -> None:
+ print(f" {self.getName()}", end="")
+ if self.isVegetarian():
+ print(f"(v)", end="")
+ print(f", {self.getPrice()}")
+ print(f" -- {self.getDescription()}")