<!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">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Plugins — Envisage Documentation</title>
<link rel="stylesheet" href="../_static/default.css" type="text/css" />
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: '../',
VERSION: '4.3.0',
COLLAPSE_INDEX: false,
FILE_SUFFIX: '.html',
HAS_SOURCE: true
};
</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>
<link rel="shortcut icon" href="../_static/et.ico"/>
<link rel="top" title="Envisage Documentation" href="../index.html" />
<link rel="up" title="Envisage Core Documentation" href="index.html" />
<link rel="next" title="How To Create a Plugin for an Envisage Application" href="howto_create_a_plugin.html" />
<link rel="prev" title="Services" href="services.html" />
</head>
<body>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="howto_create_a_plugin.html" title="How To Create a Plugin for an Envisage Application"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="services.html" title="Services"
accesskey="P">previous</a> |</li>
<li><a href="../index.html">Envisage Documentation</a> »</li>
<li><a href="index.html" accesskey="U">Envisage Core Documentation</a> »</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body">
<div class="section" id="plugins">
<h1>Plugins<a class="headerlink" href="#plugins" title="Permalink to this headline">¶</a></h1>
<p><em>Plugins</em> are used to “deliver” <a class="reference external" href="extension_points.html">Extension Points</a>, contributions to extension
points, and <a class="reference external" href="services.html">Services</a> into an Envisage application. In fact, plugins can be
thought of as simply being “delivery trucks” – they rarely (if ever) do any
<em>real</em> work themselves. In other words, plugins can do 3 things:</p>
<ol class="arabic simple">
<li>Declare extension points</li>
<li>Make contributions to extension points (including its own)</li>
<li>Create and publish services</li>
</ol>
<p>Plugins are located and managed by the <em>plugin manager</em>, and, whilst Envisage
is designed such that you can write your own plugin manager, by default, it
uses an implementation based on <a class="reference external" href="http://peak.telecommunity.com/DevCenter/PythonEggs">Python Eggs</a>.</p>
<div class="section" id="creating-a-plugin">
<h2>Creating a Plugin<a class="headerlink" href="#creating-a-plugin" title="Permalink to this headline">¶</a></h2>
<p>All plugins must implement the <a class="reference external" href="https://svn.enthought.com/enthought/browser/EnvisageCore/trunk/enthought/envisage/i_plugin.py">IPlugin</a> interface (an easy way to achieve this
is to subclass the base <a class="reference external" href="https://svn.enthought.com/enthought/browser/EnvisageCore/trunk/enthought/envisage/plugin.py">Plugin</a> class), and should provide the following
“housekeeping” information:</p>
<ul>
<li><p class="first">a globally unique identifier (e.g., “acme.motd”)</p>
<p>This obviously allows Envisage to identify a particular plugin in a sea of
other plugins. Technically, this identifier only need be unique within your
application, but since the intent is for applications to be able to include
plugins from (potentially) all over the world, using the common reverse
domain name notation is probably a good idea!</p>
</li>
<li><p class="first">a name</p>
<p>This name should be suitable for display to the user.</p>
</li>
<li><p class="first">a doc string!</p>
<p>A nice description of the intent and features of your plugin.</p>
</li>
</ul>
<p>Here is a snippet from the <a class="reference external" href="https://svn.enthought.com/enthought/browser/EnvisageCore/trunk/examples/MOTD/src/acme.motd/setup.py">acme.motd</a> plugin that is part of the <a class="reference external" href="https://svn.enthought.com/enthought/browser/EnvisageCore/trunk/examples/MOTD">Message of
the Day</a> example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">class</span> <span class="nc">MOTDPlugin</span><span class="p">(</span><span class="n">Plugin</span><span class="p">):</span>
<span class="sd">""" The 'Message of the Day' plugin.</span>
<span class="sd"> When this plugin is started it prints the 'Message of the Day' to stdout.</span>
<span class="sd"> """</span>
<span class="c">#### 'IPlugin' interface ##############################################</span>
<span class="c"># The plugin's unique identifier.</span>
<span class="nb">id</span> <span class="o">=</span> <span class="s">'acme.motd'</span>
<span class="c"># The plugin's name (suitable for displaying to the user).</span>
<span class="n">name</span> <span class="o">=</span> <span class="s">'MOTD'</span>
</pre></div>
</div>
</div>
<div class="section" id="plugin-lifecycle">
<h2>Plugin Lifecycle<a class="headerlink" href="#plugin-lifecycle" title="Permalink to this headline">¶</a></h2>
<p>Plugins have a lifecycle in the context of an application. There are currently
two key lifecycle methods on the <a class="reference external" href="https://svn.enthought.com/enthought/browser/EnvisageCore/trunk/enthought/envisage/i_plugin.py">IPlugin</a> interface:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">start</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Start the plugin.</span>
<span class="sd"> This method is called by the framework when the application is starting</span>
<span class="sd"> up. If you want to start a plugin manually use::</span>
<span class="sd"> application.start_plugin(plugin)</span>
<span class="sd"> """</span>
<span class="k">def</span> <span class="nf">stop</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Stop the plugin.</span>
<span class="sd"> This method is called by the framework when the application is</span>
<span class="sd"> stopping. If you want to stop a plugin manually use::</span>
<span class="sd"> application.stop_plugin(plugin)</span>
<span class="sd"> """</span>
</pre></div>
</div>
<p>When Envisage starts up it calls the start() method of every plugin in the
the same order that its iterator returns them in. This depends on the plugin
manager being used, but by default this will be either a) the order of the list
of plugins that was passed into the application or b) the order of the plugins
based on egg dependencies. When the application stops, it calls the stop()
method of each plugin in the reverse order that they were started in.</p>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar">
<div class="sphinxsidebarwrapper">
<p class="logo"><a href="../index.html">
<img class="logo" src="../_static/e-logo-rev.png" alt="Logo"/>
</a></p>
<h3><a href="../index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Plugins</a><ul>
<li><a class="reference internal" href="#creating-a-plugin">Creating a Plugin</a></li>
<li><a class="reference internal" href="#plugin-lifecycle">Plugin Lifecycle</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="services.html"
title="previous chapter">Services</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="howto_create_a_plugin.html"
title="next chapter">How To Create a Plugin for an Envisage Application</a></p>
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="../_sources/envisage_core_documentation/plugins.txt"
rel="nofollow">Show Source</a></li>
</ul>
<div id="searchbox" style="display: none">
<h3>Quick search</h3>
<form class="search" action="../search.html" method="get">
<input type="text" name="q" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
<p class="searchtip" style="font-size: 90%">
Enter search terms or a module, class or function name.
</p>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="howto_create_a_plugin.html" title="How To Create a Plugin for an Envisage Application"
>next</a> |</li>
<li class="right" >
<a href="services.html" title="Services"
>previous</a> |</li>
<li><a href="../index.html">Envisage Documentation</a> »</li>
<li><a href="index.html" >Envisage Core Documentation</a> »</li>
</ul>
</div>
<div class="footer">
© Copyright 2008-2011, Enthought.
Last updated on May 14, 2013.
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3.
</div>
</body>
</html>
distrib
>
Fedora
>
18
>
x86_64
>
media
>
updates
>
by-pkgid
>
c66175b08690d24bca431460aac64d89
>
files
>
261
