Source code for gramps.gui.dbguielement

#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2009       Benny Malengier
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, 
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#

"""
Group common stuff Gramps GUI elements must be able to do when tracking a DB:

   * connect to db signals
   * listen to db changes to update themself on relevant changes
   * determine if the GUI has become out of sync with the db
"""

#-------------------------------------------------------------------------
#
# GRAMPS modules
#
#-------------------------------------------------------------------------
from gramps.gen.utils.callman import CallbackManager

#-------------------------------------------------------------------------
#
# DbGUIElement class
#
#-------------------------------------------------------------------------
[docs]class DbGUIElement(object): """ Most interaction with the DB should be done via the callman attribute. On initialization, the method :meth:`_connect_db_signals` is called. Inheriting objects are advised to group the setup of the callman attribute here. .. attribute callman: a :class:`.CallbackManager` object, to be used to track specific changes in the db and set up callbacks """ def __init__(self, database): self.callman = CallbackManager(database) self._connect_db_signals() def _add_db_signal(self, name, callback): """ Convenience function to add a custom db signal. The attributes are just passed to the callman object. For primary objects, use the register method of the callman attribute. :param name: name of the signal to connect to :type name: string :param callback: function to call when signal is emitted :type callback: a funtion or method with the correct signature for the signal """ self.callman.add_db_signal(name, callback) def _connect_db_signals(self): """ Convenience method that is called on initialization of DbGUIElement. Use this to group setup of the callman attribute. Also called in _change_db method """ pass def _cleanup_callbacks(self): """ Remove all db callbacks. This is done automatically on destruction of the object, but is normally needed earlier, calling this method does so. Use _change_db method if you need to remove the callbacks because the database has changed """ database = self.callman.database if database.is_open(): #a closed database has disconnected all signals self.callman.disconnect_all() #set a new callback manager self.callman = CallbackManager(database) def _change_db(self, database): """ Change the database the GUI element works on to database. This removes all callbacks and all registered handles. :param database: the new database to connect to """ dbold = self.callman.database if dbold.is_open(): #a closed database has disconnected all signals self.callman.disconnect_all() #set a new callback manager on new database self.callman = CallbackManager(database) self._connect_db_signals()