cybertools/process/interfaces.py
helmutm b978abe473 reorganize cybertools.process; add simple action handler and work item class
git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@1280 fd906abe-77d9-0310-91a1-e0d9ade77398
2006-08-02 19:21:30 +00:00

121 lines
4.4 KiB
Python

#
# Copyright (c) 2006 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
#
"""
Interfaces for process management.
$Id$
"""
from zope.interface import Interface, Attribute
from zope import schema
from zope.i18nmessageid import MessageFactory
_ = MessageFactory('zope')
# process/workflow definitions
class IActivity(Interface):
""" A step of a process - typically a state that lets the process wait
for a user interaction or an action that is executed automatically.
"""
successors = Attribute('A set of activities following this activity')
handlerName = Attribute('Name of an adapter that may handle the '
'execution of this activity')
qualifier = Attribute('A collection of strings giving additional '
'information about an activity. '
'May be used by an execution context '
'for deciding which activity it will execute next')
def add(successor):
""" Append an activity to the collection of following activities.
"""
def execute(execution=None):
""" Execute a activity in an execution context of a process instance;
if this activity signifies a wait state this will create a work item.
If the execution argument is None a new execution context will
be created. The execution context is returned.
"""
class IProcess(Interface):
""" The definition of a process or workflow.
"""
startActivity = Attribute('The start activity of this process')
def execute():
""" Start the process (typically by executing its start activity).
Return the execution context.
"""
class IActionHandler(Interface):
""" Will be called for handling process executions. Is typically
implemented as an adapter for IActivity.
"""
def handle(execution):
""" Handles the execution of a activity in the execution context given.
"""
# process execution
class IExecution(Interface):
""" An execution context signifying the current state (or one of the
current states) of a process instance.
"""
currentActivity = Attribute('The activity this execution is currently in')
workItem = Attribute('The work item the process instance is currently '
'waiting for; None if the current activity is not in a '
'waiting state')
parent = Attribute('The execution context that has created this one '
'e.g. because of a forking operation')
children = Attribute('A collection of execution contexts that have been '
'created by this one')
def trigger(qualifiers=None):
""" A callback (handler) that will may be called by an action handler.
This will typically lead to moving on the execution context
to a successor activity of the current activity. The execution
context will use the qualifiers argument to decide which
activities to transfer control to.
"""
class IWorkItem(Interface):
""" A work item tells some external entity - typically a user - to
do something in order to let the process proceed.
"""
activity = Attribute('The activity this work item has been created from')
execution = Attribute('The execution context that has created this work item')
done = Attribute('A Boolean attribute that is true if the work '
'item has been submitted')
def submit(data={}):
""" Provide the work item with some data (optional) and have it
continue the process by triggering the execution context.
This should also set the `done` attribute to True.
"""