from Observer import _obwan, Observable
import threading
from synchlock import synchronous
class _tsobwan(_obwan):
"""Subclassed _obwan to provide thread synchronization"""
def __init__(self):
_obwan.__init__(self)
self._synchLock = threading.RLock()
setvalu = synchronous('_synchLock')(_obwan.setvalu)
subscribe = synchronous('_synchLock')(_obwan.subscribe)
_callbacks = synchronous('_synchLock')(_obwan._callbacks)
_cancel = synchronous('_synchLock')(_obwan._cancel)
class TSObservable(Observable):
"""Subclassed to provide thread synchronization"""
def __init__(self, nam ):
self.xname = "__"+nam
self.obwan = _tsobwan
# -------------------------------------------------------------------------
# example case
if __name__ == "__main__":
class MyClass(object):
""" A Class containing the observables chancellor and width"""
chancellor = TSObservable('chancellor')
width = TSObservable('width')
def __init__(self):
self.chancellor.setvalu(0)
self.width.setvalu(0)
class MyObserver(object):
"""Provides Observers for above"""
def __init__(self, name, observedObj):
self.name = name
self.subs1 = observedObj.chancellor.subscribe(self.print_c)
self.subs2 = observedObj.width.subscribe(self.print_w)
self.timesToReport = len(name)
def print_c(self, value):
print "%s observed change "%self.name, value
self.timesToReport -= 1
if self.timesToReport == 0:
print " cancelling my subscription"
self.subs1 = None
def print_w(self, value):
print "%s observed value "%self.name, value
def report2(value):
print "Report 2 observed value of ",value
import threading
import time
def onRun(observed, name):
obsver = MyObserver(name, observed)
isrunning = True
for j in range(400):
time.sleep(.10)
if isrunning and obsver.timesToReport==0:
isrunning = False
observed.chancellor = obsver.name
# ----------------------------------------------------
obnames = """Bob AllisonJane Karl Mujiburami Becky Geraldine
Johnny Barbarah Matthew""".split()
area = MyClass()
rptsbscrbr = area.width.subscribe(report2)
thrds = [ threading.Thread(target=onRun, name=n, args=(area,n))
for n in obnames]
for thrd in thrds:
thrd.start()
# lots of reports on changes to width
area.width = 4
area.width = "reddish"
# lots of reports on changes to chancellor
area.chancellor = 1.5
area.chancellor = 9
print " "
time.sleep(4.0)
# Resursing starts as thread cancel subscriptions
area.chancellor = "Amy"
# wait awhile...
time.sleep(4)
area.width =7.1
c = raw_input("ok?")
