#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2006  Donald N. Allingham
#
# 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

# $Id$

"""
Base Reference class for GRAMPS.
"""

#-------------------------------------------------------------------------
#
# RefBase class
#
#-------------------------------------------------------------------------
class RefBase(object):
    """
    Base reference class to manage references to other objects.

    Any *Ref* classes should derive from this class.
    """

    def __init__(self, source=None):
        if source:
            self.ref = source.ref
        else:
            self.ref = None

    def serialize(self):
        """
        Convert the object to a serialized tuple of data.
        """
        return self.ref

    def unserialize(self, data):
        """
        Convert a serialized tuple of data to an object.
        """
        self.ref = str(data)
        return self

    def get_referenced_handles(self):
        """
        Returns the list of (classname, handle) tuples for all directly
        referenced primary objects.
        
        :returns: Returns the list of (classname, handle) tuples for referenced 
                objects.
        :rtype: list
        """
        assert False, "Must be overridden in the derived class"

    def set_reference_handle(self, val):
        self.ref = val

    def get_reference_handle(self):
        return self.ref