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""" The default plugin manager implementation. """
# Standard library imports.
import logging
# Enthought library imports.
from enthought.traits.api import Event, HasTraits, Instance, List, implements
# Local imports.
from i_application import IApplication
from i_plugin import IPlugin
from i_plugin_manager import IPluginManager
from plugin_event import PluginEvent
# Logging.
logger = logging.getLogger(__name__)
class PluginManager(HasTraits):
""" The default plugin manager implementation. """
implements(IPluginManager)
#### 'IPluginManager' interface ###########################################
#### Events ####
# Fired when a plugin has been added to the manager.
plugin_added = Event(PluginEvent)
# Fired when a plugin has been removed from the manager.
plugin_removed = Event(PluginEvent)
#### 'PluginManager' interface ############################################
# The application that the plugin manager is part of.
application = Instance(IApplication)
#### Private interface ####################################################
# The plugins that the manager manages!
_plugins = List(IPlugin)
###########################################################################
# 'object' interface.
###########################################################################
def __init__(self, plugins=None, **traits):
""" Constructor. """
super(PluginManager, self).__init__(**traits)
# We allow the caller to specify an initial list of plugins, but the
# list itself is not part of the public API. To add and remove plugins
# after construction, use the 'add_plugin' and 'remove_plugin' methods
# respectively. The manager is also iterable, so to iterate over the
# plugins use 'for plugin in plugin_manager'.
if plugins is not None:
self._plugins = plugins
return
def __iter__(self):
""" Return an iterator over the manager's plugins. """
return iter(self._plugins)
###########################################################################
# 'IPluginManager' interface.
###########################################################################
def add_plugin(self, plugin):
""" Add a plugin to the manager. """
self._plugins.append(plugin)
self.plugin_added = PluginEvent(plugin=plugin)
return
def get_plugin(self, plugin_id):
""" Return the plugin with the specified Id. """
for plugin in self._plugins:
if plugin_id == plugin.id:
break
else:
plugin = None
return plugin
def remove_plugin(self, plugin):
""" Remove a plugin from the manager. """
self._plugins.remove(plugin)
self.plugin_removed = PluginEvent(plugin=plugin)
return
def start(self):
""" Start the plugin manager. """
map(lambda plugin: self.start_plugin(plugin), self._plugins)
return
def start_plugin(self, plugin=None, plugin_id=None):
""" Start the specified plugin. """
plugin = plugin or self.get_plugin(plugin_id)
if plugin is not None:
logger.debug('plugin %s starting', plugin.id)
plugin.activator.start_plugin(plugin)
logger.debug('plugin %s started', plugin.id)
else:
raise SystemError('no such plugin %s' % plugin_id)
return
def stop(self):
""" Stop the plugin manager. """
# We stop the plugins in the reverse order that they were started.
stop_order = self._plugins[:]
stop_order.reverse()
map(lambda plugin: self.stop_plugin(plugin), stop_order)
return
def stop_plugin(self, plugin=None, plugin_id=None):
""" Stop the specified plugin. """
plugin = plugin or self.get_plugin(plugin_id)
if plugin is not None:
logger.debug('plugin %s stopping', plugin.id)
plugin.activator.stop_plugin(plugin)
logger.debug('plugin %s stopped', plugin.id)
else:
raise SystemError('no such plugin %s' % plugin_id)
return
###########################################################################
# 'PluginManager' interface.
###########################################################################
def _application_changed(self, trait_name, old, new):
""" Static trait change handler. """
self._update_plugin_application([], self._plugins)
return
###########################################################################
# Private interface.
###########################################################################
#### Trait change handlers ################################################
def __plugins_changed(self, trait_name, old, new):
""" Static trait change handler. """
self._update_plugin_application(old, new)
return
def __plugins_items_changed(self, trait_name, old, new):
""" Static trait change handler. """
self._update_plugin_application(new.removed, new.added)
return
#### Methods ##############################################################
def _update_plugin_application(self, removed, added):
""" Update the 'application' trait of plugins added/removed. """
for plugin in removed:
plugin.application = None
for plugin in added:
plugin.application = self.application
return
#### EOF ######################################################################
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