Objective     record

1. threading.Condition Introduce

1.1 threading.Event Mechanism

1.2 threading.Event Properties and methods

2. threading.Condition Use demonstration

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Python Multithreaded programming Directory

Python Multithreaded programming -01-threading The module first

Python Multithreaded programming -02-threading modular - Use of locks

Python Multithreaded programming -03-threading modular - Condition

1. threading.Condition Introduce

1.1 threading.Event Mechanism

         stay  Python Multithreaded programming -03-threading modular - Condition Producers are introduced in - Code implementation of the consumer pattern , Used threading.Condition To control the use of the same resource pool , The producer thread and the consumer thread are equivalent , There is no master-slave . and threading.Event The mechanism is similar to the pattern of one thread giving orders to other threads , Other threads will hold a threading.Event The object of , These threads will wait for this event “ happen ”, If this never happens , Then these threads will block , Until the end of the event “ happen ”. And this kind of scene is very common .

1.2 threading.Event Properties and methods

threading.Event Properties and methods Serial number Properties and methods describe 1clear() eliminate Event Signal flags inside objects , It is set to False.2is_set()/isSet() Judge the status of internal signal signs . When using set() after ,isSet() Method returns True; When using clear() after ,isSet() Method returns False.3set() Set up Event The signal flags inside the object are True.4wait() This method only works when the internal signal is True Will be executed and returned . When the internal signal sign is False when , be wait() Wait until it is True Only return when .

2. threading.Condition Use demonstration

# Design a red street lamp ,threading.Event It is the direction of the car
# stay 10 In seconds ,4 Seconds ago, it was a red light ,4 Seconds to 8 Seconds is green , There is a red light behind

# Design a car class , Traffic lights in the direction of the car , A green light （set True） When to pass , A red light （set False） wait for
# Waiting for the most 10 second , Then turn around ; among timer It is used to indicate the second when it comes to the intersection of red street lights

# Design a walking human , Traffic lights in the direction of the car , A green light （set True） Time to wait , A red light （set False） Current
# Waiting for the most 10 second , Then turn around ; among timer It is used to indicate the second when it comes to the intersection of red street lights

%%time
import threading
import time
# Design a red street lamp ,threading.Event It is the direction of the car
# stay 10 In seconds ,4 Seconds ago, it was a red light ,4 Seconds to 8 Seconds is green , There is a red light behind
# Design a car class , Traffic lights in the direction of the car , A green light （set True） When to pass , A red light （set False） wait for
# Waiting for the most 10 second , Then turn around ; among timer It is used to indicate the second when it comes to the intersection of red street lights
class Car(threading.Thread):
def __init__(self,color,event,timer):
super().__init__()
self.color=color
self.event=event
self.timer=timer
def run(self):
time.sleep(self.timer)
count=0
while(count<11):
if(self.event.is_set()):
print(time.ctime(),"The car of {0} will thransfer ".format(self.color))
time.sleep(1)
break
else:
print(time.ctime(),"The car of {0} is waiting! ".format(self.color))
self.event.wait(10)
count+=1
if(count>=11):
print(time.ctime(),"The car of {0} is gone! ".format(self.color))
# Design a walking human , Traffic lights in the direction of the car , A green light （set True） Time to wait , A red light （set False） Current
# Waiting for the most 10 second , Then turn around ; among timer It is used to indicate the second when it comes to the intersection of red street lights
class Man(threading.Thread):
def __init__(self,name,event,timer):
super().__init__()
self.name=name
self.event=event
self.timer=timer
def run(self):
time.sleep(self.timer)
count=0
while(count<11):
if(not self.event.is_set()):
print(time.ctime(),"The man {0} will thransfer ".format(self.name))
break
else:
print(time.ctime(),"The man {0} is waiting! ".format(self.name))
time.sleep(1)
count+=1
if(count>=11):
print(time.ctime(),"The man {0} is gone! ".format(self.name))
if __name__=="__main__":
light=threading.Event()
ada=Man("ada",light,1)
ivy=Man("ivy",light,5)
allen=Man("allen",light,8)
jessica=Man("jessica",light,9)
bluecar=Car("blue",light,2)
yellowcar=Car("yellow",light,7)
whitecar=Car("white",light,9)
count=0
ada.start()
ivy.start()
allen.start()
jessica.start()
bluecar.start()
yellowcar.start()
whitecar.start()
while(count<10):
if(count==4):
light.set()
if(count==8):
light.clear()
if(light.is_set()):
print("{0} the light is {1}".format(time.ctime(),"Green"))
else:
print("{0} the light is {1}".format(time.ctime(),"Red"))
time.sleep(1)
count+=1

The operation results are as follows ：

 

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