README.md

Python Head First Design Patterns

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Chapters

chapter 1(strategy)
chapter 2(observer) (Only swing has no translation.)
chapter 3(decorator) (Only io has no translation.)
chapter 4(factory)
chapter 5(singleton)
chapter 6(command) (Only swing has no translation.)
chapter 7(adapter)
chapter 7(facade)
chapter 8(templatemethod) (applet and frame have no translation.)
chapter 9(iterator)
chapter 9(composite)
chapter 10(state)
chapter 11(proxy) (Translating this chapter is beyond my ability.)
chapter 12(combining)
chapter 12(combined) (Translating this subsection is beyond my ability.)
chapter 13 (No code)
Appendix (bridge)
Appendix (builder)
Appendix (flyweight)
Appendix (prototype)
Appendix (collections)
Appendix (ducks)
Appendix (iterenum)

Introduction

1. Translated from Head-First-Design-Patterns (java)
2. What are the differences between other Python version Head-First-Design-Patterns and ours?
   • We named the files with the same name and path as the original. (The following examples are from Chapter 1.)
     
   • We annotate the type of the code so that the code we translate is closer to the java version. (The following examples is from strategy/AnimalTest.py.)

        # our code
        from abc import ABC, abstractmethod
        from typing import List
     
     
        class AnimalTest:
            @staticmethod
            def main(*args):
                at: AnimalTest = AnimalTest()
                at.makeSomeAnimals()
     
            def makeSomeAnimals(self):
                dog: Animal = self.Dog()
                cat: Animal = self.Cat()
                # treat dogs and cats as their supertype, Animal
                animals: List[Animal] = []
                animals.append(dog)
                animals.append(cat)
                for animal in animals: animal.makeSound() # can call makeSound on any Animal

        // authors' code [https://github.com/bethrobson/Head-First-Design-Patterns/blob/master/src/headfirst/designpatterns/strategy/AnimalTest.java]
        import java.util.ArrayList;
     
        public class AnimalTest {
     
          public static void main(String[] args) {
            AnimalTest at = new AnimalTest();
            at.makeSomeAnimals();
          }
          public void makeSomeAnimals() {
            Animal dog = new Dog();
            Animal cat = new Cat();
            // treat dogs and cats as their supertype, Animal
            ArrayList<Animal> animals = new ArrayList<Animal>();
            animals.add(dog);
            animals.add(cat);
            animals.forEach(Animal::makeSound); // can call makeSound on any Animal
          }