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#------------------------------------------------------------------------------
# Copyright (c) 2005, Enthought, Inc.
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in enthought/LICENSE.txt and may be redistributed only
# under the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
# Thanks for using Enthought open source!
#
# Author: Enthought, Inc.
# Description: <Enthought naming package component>
#------------------------------------------------------------------------------
""" A monitor that detects changes to a naming context. """
# Enthought library imports.
from pyface.tree.api import NodeMonitor
class ContextMonitor(NodeMonitor):
""" A monitor that detects changes to a naming context. """
###########################################################################
# 'NodeMonitor' interface.
###########################################################################
def start(self):
""" Start listening to changes to the object. """
context = self.node.obj
context.on_trait_change(self._on_object_added, 'object_added')
context.on_trait_change(self._on_object_changed, 'object_changed')
context.on_trait_change(self._on_object_removed, 'object_removed')
context.on_trait_change(self._on_object_renamed, 'object_renamed')
context.on_trait_change(self._on_context_changed, 'context_changed')
return
def stop(self):
""" Stop listening to changes to the object. """
context = self.node.obj
context.on_trait_change(
self._on_object_added, 'object_added', remove=True
)
context.on_trait_change(
self._on_object_changed, 'object_changed', remove=True
)
context.on_trait_change(
self._on_object_removed, 'object_removed', remove=True
)
context.on_trait_change(
self._on_object_renamed, 'object_renamed', remove=True
)
context.on_trait_change(
self._on_context_changed, 'context_changed', remove=True
)
return
###########################################################################
# Private interface.
###########################################################################
#### Trait event handlers #################################################
def _on_object_added(self, event):
""" Called when an object has been added to the context. """
self.fire_nodes_inserted([event.new_binding])
return
def _on_object_changed(self, event):
""" Called when an object in the context has been changed. """
# fixme: Can we get enough information to fire a 'nodes_replaced'
# event? Something a little more granular than this!
self.fire_structure_changed()
return
def _on_object_removed(self, event):
""" Called when an object has been removed from the context. """
self.fire_nodes_removed([event.old_binding])
return
def _on_object_renamed(self, event):
""" Called when an object has been renamed in the context. """
self.fire_nodes_replaced([event.old_binding], [event.new_binding])
return
def _on_context_changed(self, event):
""" Called when a context has changed dramatically. """
self.fire_structure_changed()
return
##### EOF #####################################################################
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