design question

Sun Apr 10 06:40:40 EDT 2011

I've been wondering for weeks now how to do but I still didn't get a
satisfying answer, so I hope someone can give a hint...
I have some logs which I extract from simulation results.
These logs are in the form
timestamp, nodeid, eventname, event_argument
and now I have to analyze the data.
I don't have so many metrics to analyze but for example I might look for
"symmetric events", in the form
0.0, 0: DATA_SENT(1)
0.1, 1: DATA_RECEIVED(0)
(so in short the nodeid and the argument are swapped)
After many changes now the timeline is something as below, where
everything almost all the functions are static methods and return a new
list of events.
But now I don't get anything I like for the metrics.
Every metric only has to filter and return a result, but the problem is
that maybe for some metrics I want the result on all the nodes.
Some only the average, sometimes I want to correlated with the time (or
time slots) and so on.
So it must be very flexible, but at the same time not a pain to write...
I first wrote a class for every metric subclassing a Metric, but it
wasn't nice.
Then I tried many other ways but actually I'm a bit stuck...
Any suggestions from someone that maybe had a similar problem?

--8<---------------cut here---------------start------------->8---
class Timeline(object):
 """
 A timeline is generated by the list of events happened during the
 simulation and it's the main point to analyze the data.
 """
 def __init__(self, events=None):
 if events is None:
 self.events = []
 else:
 self.events = events
 def __str__(self):
 res = []
 for evt_tuple in iter(self):
 res.append(str(evt_tuple))
 return "\n".join(res)
 def __eq__(self, other):
 return self.events == other.events
 def __iter__(self):
 return iter(sorted(self.events, key=lambda x: x.time))
 def add(self, timestamp, nodeid, evt):
 "Add one line for the given nodeid"
 tup = EventTuple(timestamp, nodeid, evt)
 self.events.append(tup)
 def add_tuple(self, tup):
 self.events.append(tup)
 def first_event(self, _evt):
 first_evt = Timeline.filt(self.events, evt=_evt)[0]
 return pretty_time(first_evt.time)
 def sort(self):
 Timeline.sort_by(self.events)
 @staticmethod
 def sort_by(events, par='time'):
 # side effecting method
 events.sort(key=lambda x: x.__getattribute__(par))
 @staticmethod
 def filt(events, node=None, evt=None, arg=None):
 "Takes a node, an event and a function to further filter the time"
 # copy locally the events and filter them
 res = events[:]
 if node is not None:
 res = filter(lambda x: x.node == node, res)
 if evt is not None:
 res = filter(lambda x: x.evt.name == evt, res)
 if arg is not None:
 res = filter(lambda x: x.evt.arg == arg, res)
 return res
...
--8<---------------cut here---------------end--------------->8---