Python Lock Class | locked() Method with Example

Python Lock.locked() Method: Here, we are going to learn about the locked() method of Lock Class in Python with its definition, syntax, and examples.
Submitted by Hritika Rajput, on May 18, 2020

Python Lock.locked() Method

locked() is an inbuilt method of the Lock class of the threading module in Python.

This method returns True if the lock is acquired by a thread else returns False.

Module:

    from threading import Lock

Syntax:

    locked()

Parameter(s):

  • None

Return value:

The return type of this method is <class 'bool'>. It returns True is the lock is currently acquired else returns False.

Example:

# Python program to show
# the use of locked() method in Lock class

import threading
import random
                    
class shared(object):
  
    def __init__(self, x = 0):
        # Created a Lock object
        self.lock = threading.Lock()
        self.incr = x
        
        # Increment function for the thread
    def incrementcounter(self):
        print("Waiting for the lock to be unlocked")
        # Lock acquired by the current thread
        self.lock.acquire()
        print("Is the lock acquired here:", self.lock.locked())
        try:
            print('Lock acquired, current counter value: ', self.incr)
            self.incr = self.incr + 1
            print("Is the lock acquired here as well:", self.lock.locked())
        finally:
            print('Lock released, current counter value: ', self.incr)
            # Lock released by the given thread
            self.lock.release()
            print("Is the lock acquired here after release:", self.lock.locked())

def helper_thread(c):
    # Getting a random integer between 1 to 3
    r = random.randint(1,3)
    print("Random value selected:", r)
    for i in range(r):
      c.incrementcounter()
    print('Finished', str(threading.current_thread().getName()))
    print()

if __name__ == '__main__':
    obj = shared()
    thread1 = threading.Thread(target=helper_thread, args=(obj,))
    thread1.start()
    
    thread2 = threading.Thread(target=helper_thread, args=(obj,))
    thread2.start()

    thread1.join()
    thread2.join()
    
    print('Final counter value:', obj.incr)

Output

Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  0
Is the lock acquired here as well: True
Lock released, current counter value:  1
Is the lock acquired here after release: False
Finished Thread-1

Random value selected: 3
Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  1
Is the lock acquired here as well: True
Lock released, current counter value:  2
Is the lock acquired here after release: False
Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  2
Is the lock acquired here as well: True
Lock released, current counter value:  3
Is the lock acquired here after release: False
Waiting for the lock to be unlocked
Is the lock acquired here: True
Lock acquired, current counter value:  3
Is the lock acquired here as well: True
Lock released, current counter value:  4
Is the lock acquired here after release: False
Finished Thread-2

Final counter value: 4






Comments and Discussions

Ad: Are you a blogger? Join our Blogging forum.





Languages: » C » C++ » C++ STL » Java » Data Structure » C#.Net » Android » Kotlin » SQL
Web Technologies: » PHP » Python » JavaScript » CSS » Ajax » Node.js » Web programming/HTML
Solved programs: » C » C++ » DS » Java » C#
Aptitude que. & ans.: » C » C++ » Java » DBMS
Interview que. & ans.: » C » Embedded C » Java » SEO » HR
CS Subjects: » CS Basics » O.S. » Networks » DBMS » Embedded Systems » Cloud Computing
» Machine learning » CS Organizations » Linux » DOS
More: » Articles » Puzzles » News/Updates


© https://www.includehelp.com some rights reserved.