example.py

# Copyright (c) 2018 Gabriele Baldoni.
#
# See the NOTICE file(s) distributed with this work for additional
# information regarding copyright ownership.
#
# This program and the accompanying materials are made available under the
# terms of the Eclipse Public License 2.0 which is available at
# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
# which is available at https://www.apache.org/licenses/LICENSE-2.0.
#
# SPDX-License-Identifier: Apache-2.0
#
# Contributors: Gabriele Baldoni MVar implementation in Python

import time
from threading import Thread
from random import randint
from mvar import MVar


def worker(var):
    time.sleep(randint(1, 3))
    var.put(1)


def worker2(var):
    var.put(3)


print('Starting Worker1 and waiting on MVar the result...')
local_var = MVar()
Thread(target=worker, args=(local_var,), daemon=True).start()
res = local_var.take()
print("Worker1 returned {}".format(res))
print("Putting a value on the MVar to block Worker2")
local_var.put(2)
print('Starting Worker2...')
Thread(target=worker2, args=(local_var,), daemon=True).start()
res2 = local_var.take()
print("Getting previous value stored in MVar to"
      "unlock Worker2 - MVar.take() returned {}".format(res2))
res3 = local_var.take()
print("Worker3 returned {}".format(res3))