Merge pull request faif#1 from faif/master

Update from original

Author: diopib

.gitignore

@@ -0,0 +1 @@
+__pycache__

3-tier.py

@@ -3,35 +3,43 @@
 
 
 classData(object):
+""" Data Store Class """
 
 products={
 'milk':{'price': 1.50, 'quantity': 10},
 'eggs':{'price': 0.20, 'quantity': 100},
 'cheese':{'price': 2.00, 'quantity': 10}
  }
 
+def__get__(self, obj, klas):
+print ("(Fetching from Data Store)")
+return{'products': self.products}
+
 
 classBusinessLogic(object):
 
-def__init__(self):
-self.data=Data()
+""" Business logic holding data store instances """
+
+data=Data()
 
 defproduct_list(self):
-returnself.data.products.keys()
+returnself.data['products'].keys()
 
 defproduct_information(self, product):
-returnself.data.products.get(product, None)
+returnself.data['products'].get(product, None)
 
 
 classUi(object):
+""" UI interaction class """
 
 def__init__(self):
 self.business_logic=BusinessLogic()
 
 defget_product_list(self):
 print('PRODUCT LIST:')
 forproductinself.business_logic.product_list():
-print(product)
+#print(product)
+yieldproduct
 print('')
 
 defget_product_information(self, product):
@@ -56,3 +64,16 @@ def main():
 
 if__name__=='__main__':
 main()
+
+### OUTPUT ###
+# (Fetching from Data Store)
+# PRODUCT INFORMATION:
+# Name: Cheese, Price: 2.00, Quantity: 10
+# (Fetching from Data Store)
+# PRODUCT INFORMATION:
+# Name: Eggs, Price: 0.20, Quantity: 100
+# (Fetching from Data Store)
+# PRODUCT INFORMATION:
+# Name: Milk, Price: 1.50, Quantity: 10
+# (Fetching from Data Store)
+# That product "arepas" does not exist in the records

README.md

@@ -1,34 +1,41 @@
 python-patterns
 ===============
 
-A collection of design patterns implemented (by other people) in python
+A collection of design patterns and idioms in Python.
+
+When an implementation is added or modified, be sure to update this file and
+rerun `append_output.sh` (eg. ./append_output.sh borg.py) to keep the output
+comments at the bottom up to date.
 
 Current Patterns:
 
-* 3-tier 
-* composite 
-* mvc
-* decorator 
-* null
-* facade 
-* observer
-* abstract_factory 
-* factory_method 
-* pool
-* adapter 
-* flyweight 
-* prototype
-* borg 
-* proxy
-* bridge 
-* graph_search 
-* state
-* builder 
-* iterator 
-* strategy
-* chain 
-* mediator 
-* template
-* command 
-* memento 
-* visitor
+| Pattern | Description |
+|:-------:| ----------- |
+|[3-tier](3-tier.py)| data<->business logic<->presentation separation (strict relationships) |
+|[abstract_factory](abstract_factory.py)| use a generic function with specific factories |
+|[adapter](adapter.py)| adapt one interface to another using a whitelist |
+|[borg](borg.py)| a singleton with shared-state among instances |
+|[bridge](bridge.py)| a client-provider middleman to soften interface changes |
+|[builder](builder.py)| call many little discrete methods rather than having a huge number of constructor parameters |
+|[catalog](catalog.py)| general methods will call different specialized methods based on construction parameter |
+|[chain](chain.py)| apply a chain of successive handlers to try and process the data |
+|[command](command.py)| bundle a command and arguments to call later |
+|[composite](composite.py)| encapsulate and provide access to a number of different objects |
+|[decorator](decorator.py)| wrap functionality with other functionality in order to affect outputs |
+|[facade](facade.py)| use one class as an API to a number of others |
+|[factory_method](factory_method.py)| delegate a specialized function/method to create instances |
+|[flyweight](flyweight.py)| transparently reuse existing instances of objects with similar/identical state |
+|[graph_search](graph_search.py)| (graphing algorithms, not design patterns) |
+|[mediator](mediator.py)| an object that knows how to connect other objects and act as a proxy |
+|[memento](memento.py)| generate an opaque token that can be used to go back to a previous state |
+|[mvc](mvc.py)| model<->view<->controller (non-strict relationships) |
+|[observer](observer.py)| provide a callback for notification of events/changes to data |
+|[pool](pool.py)| preinstantiate and maintain a group of instances of the same type |
+|[prototype](prototype.py)| use a factory and clones of a prototype for new instances (if instantiation is expensive) |
+|[proxy](proxy.py)| an object funnels operations to something else |
+|[publish_subscribe](publish_subscribe.py)| a source syndicates events/data to 0+ registered listeners |
+|[state](state.py)| logic is org'd into a discrete number of potential states and the next state that can be transitioned to |
+|[strategy](strategy.py)| selectable operations over the same data |
+|[template](template.py)| an object imposes a structure but takes pluggable components |
+|[visitor](visitor.py)| invoke a callback for all items of a collection |
+|[chaining_method](chaining_method.py)| continue callback next object method |

__pycache__/facade.cpython-33.pyc

@@ -1,32 +1,34 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
 # http://ginstrom.com/scribbles/2007/10/08/design-patterns-python-style/
 
 """Implementation of the abstract factory pattern"""
 
 importrandom
 
-
 classPetShop:
+
 """A pet shop"""
 
 def__init__(self, animal_factory=None):
-"""pet_factory is our abstract factory.
- We can set it at will."""
+"""pet_factory is our abstract factory. We can set it at will."""
 
 self.pet_factory=animal_factory
 
 defshow_pet(self):
-"""Creates and shows a pet using the
- abstract factory"""
+"""Creates and shows a pet using the abstract factory"""
 
 pet=self.pet_factory.get_pet()
-print("This is a lovely{}".format(pet))
+print("We have a lovely{}".format(pet))
 print("It says{}".format(pet.speak()))
-print("It eats{}".format(self.pet_factory.get_food()))
+print("We also have{}".format(self.pet_factory.get_food()))
 
 
 # Stuff that our factory makes
 
 classDog:
+
 defspeak(self):
 return"woof"
 
@@ -35,6 +37,7 @@ def __str__(self):
 
 
 classCat:
+
 defspeak(self):
 return"meow"
 
@@ -45,6 +48,7 @@ def __str__(self):
 # Factory classes
 
 classDogFactory:
+
 defget_pet(self):
 returnDog()
 
@@ -53,13 +57,13 @@ def get_food(self):
 
 
 classCatFactory:
+
 defget_pet(self):
 returnCat()
 
 defget_food(self):
 return"cat food"
 
-
 # Create the proper family
 defget_factory():
 """Let's be dynamic!"""
@@ -68,8 +72,21 @@ def get_factory():
 
 # Show pets with various factories
 if__name__=="__main__":
-shop=PetShop()
 foriinrange(3):
-shop.pet_factory=get_factory()
+shop=PetShop(get_factory())
 shop.show_pet()
 print("="*20)
+
+### OUTPUT ###
+# We have a lovely Dog
+# It says woof
+# We also have dog food
+# ====================
+# We have a lovely Dog
+# It says woof
+# We also have dog food
+# ====================
+# We have a lovely Cat
+# It says meow
+# We also have cat food
+# ====================

__pycache__/mediator.cpython-33.pyc

@@ -1,41 +1,38 @@
-# http://ginstrom.com/scribbles/2008/11/06/generic-adapter-class-in-python/
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
 
-importos
+"""http://ginstrom.com/scribbles/2008/11/06/generic-adapter-class-in-python/"""
 
+importos
 
 classDog(object):
 def__init__(self):
 self.name="Dog"
-
 defbark(self):
 return"woof!"
 
-
 classCat(object):
 def__init__(self):
 self.name="Cat"
-
 defmeow(self):
 return"meow!"
 
-
 classHuman(object):
 def__init__(self):
 self.name="Human"
-
 defspeak(self):
 return"'hello'"
 
 
 classCar(object):
 def__init__(self):
 self.name="Car"
-
 defmake_noise(self, octane_level):
 return"vroom{0}".format("!"*octane_level)
 
 
 classAdapter(object):
+
 """
  Adapts an object by replacing methods.
  Usage:
@@ -60,6 +57,7 @@ class Adapter(object):
  A Human goes 'hello'
  A Car goes vroom!!!
  """
+
 def__init__(self, obj, adapted_methods):
 """We set the adapted methods in the object's dict"""
 self.obj=obj
@@ -86,5 +84,10 @@ def main():
 
 
 if__name__=="__main__":
-importdoctest
-doctest.testmod()
+main()
+
+### OUTPUT ###
+# A Dog goes woof!
+# A Cat goes meow!
+# A Human goes 'hello'
+# A Car goes vroom!!!

__pycache__/null.cpython-33.pyc

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+set -e
+
+src=$(sed -n -e '/### OUTPUT ###/,$!p'"$1")
+output=$(python "$1"| sed 's/^/# /')
+
+# These are done separately to avoid having to insert a newline, which causes
+# problems when the text itself has '\n' in strings
+echo"$src">$1
+echo -e "\n### OUTPUT ###">>$1
+echo"$output">>$1

abstract_factory.py

@@ -1,8 +1,13 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+
 classBorg:
 __shared_state={}
 
 def__init__(self):
 self.__dict__=self.__shared_state
+self.state='Init'
 
 def__str__(self):
 returnself.state
@@ -18,19 +23,30 @@ class YourBorg(Borg):
 rm1.state='Idle'
 rm2.state='Running'
 
-print('rm1:', rm1)
-print('rm2:', rm2)
+print('rm1:{0}'.format(rm1))
+print('rm2:{0}'.format(rm2))
 
 rm2.state='Zombie'
 
-print('rm1:', rm1)
-print('rm2:', rm2)
+print('rm1:{0}'.format(rm1))
+print('rm2:{0}'.format(rm2))
 
-print('rm1 id:', id(rm1))
-print('rm2 id:', id(rm2))
+print('rm1 id:{0}'.format(id(rm1)))
+print('rm2 id:{0}'.format(id(rm2)))
 
 rm3=YourBorg()
 
-print('rm1:', rm1)
-print('rm2:', rm2)
-print('rm3:', rm3)
+print('rm1:{0}'.format(rm1))
+print('rm2:{0}'.format(rm2))
+print('rm3:{0}'.format(rm3))
+
+### OUTPUT ###
+# rm1: Running
+# rm2: Running
+# rm1: Zombie
+# rm2: Zombie
+# rm1 id: 140732837899224
+# rm2 id: 140732837899296
+# rm1: Init
+# rm2: Init
+# rm3: Init