On 11/30/2011 07:51 AM, osimons wrote:
...
Subclassing components is not an encouraged development pattern with
Trac. The one or two places where we subclass in Trac (like the
WikiMacroBase) the components are clearly marked as "abstract = True"
to ensure that responsibilities are clearly set. Making complex
hierarchies of components that implement and override methods and data
will be a painful development and maintenance experience.
Trac can only guarantee that we call the component constructor
(__init__()) and the rest must be up to you. ...
"Try to avoid subclassing components" is the best advice,
really... :-)
I accept that fixing this now would inconvenience lots of developers and
I don't mind jumping through a hoop or two to do my own subclassing
rather than having it happen by magic but not using subclasses is going
to make my implementation very awkward. I have:
* A SimpleScheduler - uses built-in assumptions 8-hour work days,
Monday-Friday
* A CalendarScheduler - Exactly like a SimpleScheduler except it uses
an extension point to access a pluggable calendar implementation
* A ResourceScheduler - Exactly like a CalendarScheduler except it
keeps track of resource usage
If I can't do:
class SimpleScheduler(Component):
...
class CalendarSchduler(SimpleScheduler):
...
class ResourceScheduler(CalendarSchduler):
...
then I have a *lot* of duplicate code in the classes.
Is all I have to do:
...
class CalendarSchduler(SimpleScheduler):
def __init__(self):
# Pass self explicitly due to Component limitations
SimpleScheduler.__init__(self)
...
? If so, I'm good.
Chris
--
Christopher Nelson, Software Engineering Manager
SIXNET - Solutions for Your Industrial Networking Challenges
331 Ushers Road, Ballston Lake, NY 12019
Tel: +1.518.877.5173, Fax: +1.518.877.8346 www.sixnet.com
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