Cadoles
/
formations
20
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
formations/python/python3/fr/_build/html/DesignPatterns.html

190 lines
10 KiB
HTML
Raw Normal View History

en and fr python3 courses
2018-08-21 10:25:44 +02:00
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="fr">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Les design patterns &#8212; Documentation Formation Python 1</title>
<link rel="stylesheet" href="_static/classic.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: './',
VERSION: '1',
COLLAPSE_INDEX: false,
FILE_SUFFIX: '.html',
HAS_SOURCE: true,
SOURCELINK_SUFFIX: '.txt'
};
</script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<script type="text/javascript" src="_static/translations.js"></script>
<link rel="index" title="Index" href="genindex.html" />
<link rel="search" title="Recherche" href="search.html" />
<link rel="next" title="La librairie standard" href="stdlib.html" />
<link rel="prev" title="Le style de programmation par exceptions" href="exceptions.html" />
</head>
<body>
<div style="background-color: white; text-align: left; padding: 10px 10px 15px 15px">
<table><tr><td>
<img src="_static/sphinx.png" alt="logo" />
</td><td>
<h1>&nbsp; &nbsp; Programmation python</h1>
</td></tr></table>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="Index général"
accesskey="I">index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Index des modules Python"
>modules</a> |</li>
<li class="right" >
<a href="stdlib.html" title="La librairie standard"
accesskey="N">suivant</a> |</li>
<li class="right" >
<a href="exceptions.html" title="Le style de programmation par exceptions"
accesskey="P">précédent</a> |</li>
<a href="index.html">Programmation python </a> &raquo;
</ul>
</div>
<p>&nbsp;</p>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="les-design-patterns">
<h1>Les design patterns<a class="headerlink" href="#les-design-patterns" title="Lien permanent vers ce titre"></a></h1>
<p>Les design patterns <strong>ne sont pas</strong> indépendants du langage.
Ils dépendent de l’implémentation.</p>
<div class="section" id="le-duck-typing">
<h2>Le duck typing<a class="headerlink" href="#le-duck-typing" title="Lien permanent vers ce titre"></a></h2>
<p>En python, le duck typing est une forme extreme de programmation par interface.
Ne pas hériter dans des directions fausse</p>
<p>exemple : une voiture ne peut hériter d’un moteur, parce que un moteur n’est pas une voiture.</p>
</div>
<div class="section" id="hold-or-wrap">
<h2>hold or wrap ?<a class="headerlink" href="#hold-or-wrap" title="Lien permanent vers ce titre"></a></h2>
<p><strong>hold</strong>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">O</span><span class="o">.</span><span class="n">S</span><span class="o">.</span><span class="n">method</span><span class="p">()</span>
</pre></div>
</div>
<p>Cela induit un couplage fort (cf la loi de Demeter)</p>
<div class="admonition important">
<p class="first admonition-title">Important</p>
<p class="last">law of Demeter : never more than one dot.</p>
</div>
<p>wrap : a hold by private name, with a:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="bp">self</span><span class="o">.</span><span class="n">S</span><span class="o">.</span><span class="n">method</span><span class="p">()</span>
</pre></div>
</div>
<p>Ou bien une méthode getattr:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="fm">__getattr__</span><span class="p">()</span>
</pre></div>
</div>
<p>Gets coupling right.</p>
</div>
<div class="section" id="wrapper-can-restrict-inheritance-cannot-restrict">
<h2>wrapper can restrict, inheritance cannot restrict<a class="headerlink" href="#wrapper-can-restrict-inheritance-cannot-restrict" title="Lien permanent vers ce titre"></a></h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">RestrictingWrapper</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">w</span><span class="p">,</span> <span class="n">block</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_w</span> <span class="o">=</span> <span class="n">w</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_block</span> <span class="o">=</span> <span class="n">block</span>
<span class="k">def</span> <span class="nf">__getattr__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">n</span><span class="p">):</span>
<span class="k">if</span> <span class="n">n</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_block</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">AttributeError</span><span class="p">,</span> <span class="n">n</span>
<span class="k">return</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_w</span><span class="p">,</span> <span class="n">n</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="pattern-de-creation-singleton">
<h2>Pattern de création : singleton<a class="headerlink" href="#pattern-de-creation-singleton" title="Lien permanent vers ce titre"></a></h2>
<p># utiliser un module au lieu d’une classe</p>
<p>in <cite>toto.py</cite>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Toto</span><span class="p">()</span>
<span class="n">toto</span> <span class="o">=</span> <span class="n">Toto</span><span class="p">()</span>
</pre></div>
</div>
<p>in another module:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">toto</span> <span class="k">import</span> <span class="n">toto</span>
</pre></div>
</div>
</div>
<div class="section" id="la-factory">
<h2>la factory<a class="headerlink" href="#la-factory" title="Lien permanent vers ce titre"></a></h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">load</span><span class="p">(</span><span class="n">pkg</span><span class="p">,</span> <span class="n">obj</span><span class="p">):</span>
<span class="n">m</span> <span class="o">=</span> <span class="nb">__import__</span><span class="p">(</span><span class="n">pkg</span><span class="p">,</span> <span class="p">{},</span> <span class="p">{},</span> <span class="p">[</span><span class="n">obj</span><span class="p">])</span>
<span class="k">return</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">m</span><span class="p">,</span> <span class="n">obj</span><span class="p">)</span>
<span class="bp">cls</span> <span class="o">=</span> <span class="n">load</span><span class="p">(</span><span class="s1">&#39;p1.p2.p3&#39;</span><span class="p">,</span> <span class="s1">&#39;c4&#39;</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="template-method-self-delegation">
<h2>template method (self delegation)<a class="headerlink" href="#template-method-self-delegation" title="Lien permanent vers ce titre"></a></h2>
<p># Abstract base class:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">def</span> <span class="nf">OrganiseMethod</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">org_method</span><span class="p">():</span>
<span class="k">def</span> <span class="nf">do_this</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">do_that</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">Concrete</span><span class="p">(</span><span class="n">OrganiseMethod</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">do_this</span><span class="p">():</span> <span class="o">...</span>
<span class="k">def</span> <span class="nf">do_that</span><span class="p">():</span> <span class="o">...</span>
</pre></div>
</div>
<p>il est préférable de lever une NotImplementedError, ce qui revient à faire
une classe abstraite.</p>
</div>
</div>
</div>
</div>
</div>
<div style="background-color: white; text-align: left; padding: 10px 10px 15px 15px">
<a href="search.html"> Recherche</a> | &nbsp;
<!-- a href="genindex.html"> Genindex</a-->
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="genindex.html" title="Index général"
>index</a></li>
<li class="right" >
<a href="py-modindex.html" title="Index des modules Python"
>modules</a> |</li>
<li class="right" >
<a href="stdlib.html" title="La librairie standard"
>suivant</a> |</li>
<li class="right" >
<a href="exceptions.html" title="Le style de programmation par exceptions"
>précédent</a> |</li>
<a href="index.html">Programmation python </a> &raquo;
</ul>
</div>
<div class="footer" role="contentinfo">
&#169; Copyright 2015, cadoles (www.cadoles.com).
Créé avec <a href="http://sphinx-doc.org/">Sphinx</a> 1.6.7.
</div>
</body>
</html>