#
#  Copyright (c) 2004 Helmut Merz helmutm@cy55.de
#
#  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
#

"""
Definition of the Task class.

$Id$
"""

from zope.interface import implements

from entity import Entity
from interfaces import ITask


class Task(Entity):
    """ A Task is a scheduled piece of work.
        Resources may be allocated to a Task.
        A Task may depend on subtasks.
    """

    implements(ITask)

    title = u''
    #title = property(_getTitle, _setTitle)

    _subtasks = []
    _parentTasks = []

    def getSubtasks(self, taskTypes=None):
        return tuple(self._subtasks)

    def getParentTasks(self, taskTypes=None):
        return tuple(self._parentTasks)

    def assignSubtask(self, task):
        self._subtasks.append(task)
        task._parentTasks.append(self)
        return task