A collection of design patterns/idioms in Python
Python Shell
Latest commit 2ccf769 Aug 23, 2016 @faif committed on GitHub Merge pull request #153 from Xuefeng-Zhu/patch-3
simplify public_subscribe update
Permalink
Failed to load latest commit information.
.gitignore Remove __pycache__ and add __pycache__ to .gitignore Dec 29, 2013
.travis.yml BF(TEMP): Disabled pypy for now -- gets stuck May 17, 2016
3-tier.py BF: descriptors must be bound to class, not instance -- Revert "Adjus… May 17, 2016
README.md Small grammatical clarification Oct 28, 2015
__init__.py add: basic unittest test Jan 8, 2016
abstract_factory.py Pep8 check for abstract_factory.py Mar 27, 2015
adapter.py BF: fixing docstring to pass doctest in adapter.py and import print_f… May 17, 2016
append_output.sh added the state variable to borg and improved the README May 5, 2014
borg.py added the state variable to borg and improved the README May 5, 2014
bridge.py Your code is too weak for PEP8. You lack DISCIPLINE Mar 19, 2014
builder.py Update builder.py Jan 30, 2016
catalog.py fix docstrings Mar 24, 2016
chain.py BF(PY3): use next() instead of .next() (PY3 only) May 17, 2016
chaining_method.py BF: fixing docstring to pass doctest in adapter.py and import print_f… May 17, 2016
classes_hsm.png add: pyreverse class diagrams Jun 6, 2016
classes_test_hsm.png add: pyreverse class diagrams Jun 6, 2016
command.py BF/ENH: assure that foo.txt exists and no conflicts for demonstration May 17, 2016
composite.py Revert "edit the publish_subscribe.py" Sep 20, 2014
decorator.py ENH: have shebangs consistently in every file with __name__ == "__mai… May 17, 2016
delegation_pattern.py for uniformity -- no exec bit on delegation_pattern.py May 17, 2016
facade.py ENH: reduce sleep to 0.1 for consistency May 17, 2016
factory_method.py improved readability Jan 15, 2016
flyweight.py TEMP workaround: flyweight is not compatible with Python3 May 17, 2016
front_controller.py minor edit May 28, 2015
graph_search.py fix minor issue Aug 22, 2016
hsm.py change: EAFP refactoring of HierarchicalStateMachine._next_state() May 13, 2016
iterator.py add __future__ print_function as print(number, end=' ') won't work in… Apr 30, 2015
lazy_evaluation.py correct lazy_evaluation output Aug 3, 2016
mediator.py Your code is too weak for PEP8. You lack DISCIPLINE Mar 19, 2014
memento.py deepcopy logic inverted Nov 22, 2015
mvc.py Duplicate word in comments Mar 7, 2016
observer.py Minor pep8 changes. Most salient is that membership test should be 'x… Apr 20, 2014
pool.py Your code is too weak for PEP8. You lack DISCIPLINE Mar 19, 2014
prototype.py Updated docstring. Feb 23, 2016
proxy.py ENH: reduce sleep to 0.1 for consistency May 17, 2016
publish_subscribe.py simplify public_subscribe update Aug 23, 2016
registry.py Fix a small error in registry pattern. Aug 19, 2015
run_all.sh BF: moved running all the scripts via coverage into a separate helper… May 17, 2016
specification.py add output to the bottom of the specification.py and adaptation with … Jun 7, 2015
state.py ENH: have shebangs consistently in every file with __name__ == "__mai… May 17, 2016
strategy.py ENH: have shebangs consistently in every file with __name__ == "__mai… May 17, 2016
template.py Add output to bottom of scripts Feb 1, 2014
test_abstract_factory.py BF(PY2): use mock module if no unittest.mock is available May 17, 2016
test_adapter.py ENH: have shebangs consistently in every file with __name__ == "__mai… May 17, 2016
test_borg.py ENH: have shebangs consistently in every file with __name__ == "__mai… May 17, 2016
test_bridge.py ENH: pragma: no cover for conditioning of mock imports May 17, 2016
test_command.py ENH: have shebangs consistently in every file with __name__ == "__mai… May 17, 2016
test_flyweight.py ENH: pragma: no cover for conditioning of mock imports May 17, 2016
test_hsm.py BF: dedent few assertions out of with assertRaises cm May 17, 2016
test_observer.py BF(PY2): use mock module if no unittest.mock is available May 17, 2016
test_proxy.py BF(TST): fixing test_proxy for recent decrease of sleep, but also py … May 17, 2016
test_publish_subscribe.py ENH: pragma: no cover for conditioning of mock imports May 17, 2016
test_state.py ENH: have shebangs consistently in every file with __name__ == "__mai… May 17, 2016
test_strategy.py BF: minor typo unit[t]est May 17, 2016
visitor.py Your code is too weak for PEP8. You lack DISCIPLINE Mar 19, 2014

README.md

python-patterns

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:

Creational Patterns:

Pattern Description
abstract_factory use a generic function with specific factories
borg a singleton with shared-state among instances
builder instead of using multiple constructors, builder object receives parameters and returns constructed objects
factory_method delegate a specialized function/method to create instances
lazy_evaluation lazily-evaluated property pattern in Python
pool preinstantiate and maintain a group of instances of the same type
prototype use a factory and clones of a prototype for new instances (if instantiation is expensive)

Structural Patterns:

Pattern Description
3-tier data<->business logic<->presentation separation (strict relationships)
adapter adapt one interface to another using a white-list
bridge a client-provider middleman to soften interface changes
composite encapsulate and provide access to a number of different objects
decorator wrap functionality with other functionality in order to affect outputs
facade use one class as an API to a number of others
flyweight transparently reuse existing instances of objects with similar/identical state
front_controller single handler requests coming to the application
mvc model<->view<->controller (non-strict relationships)
proxy an object funnels operations to something else

Behavioral Patterns:

Pattern Description
chain apply a chain of successive handlers to try and process the data
catalog general methods will call different specialized methods based on construction parameter
chaining_method continue callback next object method
command bundle a command and arguments to call later
mediator an object that knows how to connect other objects and act as a proxy
memento generate an opaque token that can be used to go back to a previous state
observer provide a callback for notification of events/changes to data
publish_subscribe a source syndicates events/data to 0+ registered listeners
registry keep track of all subclasses of a given class
specification business rules can be recombined by chaining the business rules together using boolean logic
state logic is organized into a discrete number of potential states and the next state that can be transitioned to
strategy selectable operations over the same data
template an object imposes a structure but takes pluggable components
visitor invoke a callback for all items of a collection

Others:

Pattern Description
graph_search (graphing algorithms, not design patterns)