from threading import Thread
LARGE = 100000
class Future:
def __init__(self, f):
self.__f = f
self.__thread = None
self.__exception = None
def __call__(self, *args, **kw):
self.__thread = Thread(target=self.runfunc, args=args, kwargs=kw)
self.__thread.start()
return self
def runfunc(self, *args, **kw):
try:
self.__val = self.__f(*args, **kw)
except Exception, e:
self.__exception = e
def __coerce__(self, other):
return (self.__val, other)
def __getattr__(self, name):
self.__thread.join()
if self.__exception is not None:
raise self.__exception
out = getattr(self.__val, name)
return out
def future(f):
return Future(f)
@future
def long_running():
print 'Starting long_running()'
out = 0
for i in range(LARGE):
out += 1
print 'Done with long_running()'
return out
@future
def long_str():
print 'Starting long_running()'
out = 0
for i in range(LARGE):
out += 1
print 'Done with long_running()'
return str(out)
@future
def raises():
raise Exception('This is a test')
print 'Getting value result from long running'
v = long_running()
print 'Doing other stuff ...'
print 'Use result of long_running()'
print v, LARGE
print v + v
print v
print xrange(v)
v = long_str()
print v[0]
print v * 2
print v.split
v = raises()
print v
# RESULT
'''
>>> import deferred
Getting value result from long running
Starting long_running()
Doing other stuff ...
Use result of long_running()
Done with long_running()
100000 100000
200000
100000
xrange(100000)
Starting long_running()
Done with long_running()
1
100000100000
<built-in method split of str object at 0x00B4E5C0>
Traceback (most recent call last):
File "<pyshell#1>", line 1, in -toplevel-
import deferred
File "C:\Python\Python24\deferred.py", line 72, in -toplevel-
print v
File "C:\Python\Python24\deferred.py", line 27, in __getattr__
raise self.__exception
Exception: This is a test
>>>
'''
