/
dispatcher.py
164 lines (135 loc) · 5.73 KB
/
dispatcher.py
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from driver import Driver
from rider import Rider
from location import *
class Dispatcher:
"""A dispatcher fulfills requests from riders and drivers for a
ride-sharing service.
When a rider requests a driver, the dispatcher assigns a driver to the
rider. If no driver is available, the rider is placed on a waiting
list for the next available driver. A rider that has not yet been
picked up by a driver may cancel their request.
When a driver requests a rider, the dispatcher assigns a rider from
the waiting list to the driver. If there is no rider on the waiting list
the dispatcher does nothing. Once a driver requests a rider, the driver
is registered with the dispatcher, and will be used to fulfill future
rider requests.
"""
# === Private Attribute ===
# @type drivers: list
# The list of all drivers who are registered.
# When a driver requests a rider
# for the 1st time, he is registered even no rider is assigned to.
# @type waiting_riders: list
# The list of all riders who are waiting for an assigned driver within their patience.
# When a rider requests a driver, he will be placed to the waiting list
# if no driver is available then.
def __init__(self):
"""Initialize a Dispatcher.
@param self: Dispatcher
@rtype: None
>>> dispatcher = Dispatcher()
>>>
"""
self.drivers = []
self.waiting_riders = []
def __str__(self):
"""Return a string representation.
@param self: Dispatcher
@rtype: str
>>> dispatcher = Dispatcher()
>>> print(dispatcher)
Drivers in idle:
Drivers in driving:
Riders in waiting:
<BLANKLINE>
"""
drivers_idle = 'Drivers in idle:\n'
drivers_driving = 'Drivers in driving:\n'
riders_waiting = 'Riders in waiting:\n'
for driver in self.drivers:
if driver.is_idle():
drivers_idle += '\t{},{}\n'.format(driver.id, driver.location)
else:
drivers_driving += '\t{},{}\n'.format(driver.id, driver.location)
for rider in self.waiting_riders:
riders_waiting += '\t{}, {}, {}\n'.format(rider.id, rider.origin,
rider.destination)
return drivers_idle + drivers_driving + riders_waiting
def request_driver(self, rider):
"""Return a driver for the rider, or None if no driver is available.
If there are multiple drivers available, the dispatcher returns the
quickest driver based on the driving time.
Add the rider to the waiting list if no driver is available.
@param self: Dispatcher
@param rider: Rider
@rtype: Driver | None
>>> rider_Bathe = Rider('Bathe', 'waiting', 5, Location(1,2), Location(5,8))
>>> dispatcher = Dispatcher()
>>> print(dispatcher.request_driver(rider_Bathe))
None
>>> print(len(dispatcher.waiting_riders))
1
"""
available_drivers = []
rider.status = "waiting"
for driver in self.drivers:
if driver.is_idle():
time = driver.get_travel_time(rider.origin)
available_drivers.append((time, driver))
if len(available_drivers) == 0:
self.waiting_riders.append(rider)
return None
else:
available_drivers.sort(key=lambda x: x[0])
fastest_driver = available_drivers.pop(0)
available_drivers.clear()
return fastest_driver[1]
def request_rider(self, driver):
"""Return a rider for the driver, or None if no rider is available.
If this is a new driver, register the driver for future rider requests.
@param self: Dispatcher
@param driver: Driver
@rtype: Rider | None
>>> dispatcher = Dispatcher()
>>> rider_Bathe = Rider('Bathe','waiting', 5, Location(1,2), Location(5,8))
>>> print(dispatcher.request_driver(rider_Bathe))
None
>>> driver_Atom = Driver('Atom', Location(10,9), 1)
>>> print(dispatcher.request_rider(driver_Atom))
Rider_ID: Bathe, status: waiting, patience: 5, origin: (1,2), destination: (5,8)
"""
if driver not in self.drivers:
self.drivers.append(driver)
if len(self.waiting_riders) > 0:
return self.waiting_riders.pop(0)
else:
return None
def cancel_ride(self, rider):
"""Cancel the ride request for the rider if he is on the
waiting list and the patience runs out.
@param self: Dispatcher
@param rider: Rider
@rtype: None
>>> rider_Bathe = Rider('Bathe','waiting', 5, Location(1,2), Location(5,8))
>>> dispatcher = Dispatcher()
>>> print(dispatcher.request_driver(rider_Bathe))
None
>>> print(dispatcher.cancel_ride(rider_Bathe))
None
"""
try:
self.waiting_riders.remove(rider)
except IndexError:
print('No waiting riders!!!')
except ValueError:
print('The rider is not waiting!!!')
if __name__ == "__main__":
import doctest
doctest.testmod()
dispatcher = Dispatcher()
rider1 = Rider('rider1', 'waiting', 5, Location(1, 2), Location(5, 8))
driver1 = Driver('driver1', Location(10, 9), 1)
print(dispatcher.request_driver(rider1))
print(dispatcher.request_rider(driver1))
dispatcher.cancel_ride(rider1)
print(dispatcher)