class ElevatorLogic(object):
"""
An incorrect implementation. Can you make it pass all the tests?
Fix the methods below to implement the correct logic for elevators.
The tests are integrated into `README.md`. To run the tests:
$ python -m doctest -v README.md
To learn when each method is called, read its docstring.
To interact with the world, you can get the current floor from the
`current_floor` property of the `callbacks` object, and you can move the
elevator by setting the `motor_direction` property. See below for how this
is done.
"""
def __init__(self):
self.callbacks = None
self._direction = None
self._requests = Requests()
def on_called(self, floor, direction):
"""
This is called when somebody presses the up or down button to call the
elevator.
This could happen at any time, whether or not the elevator is moving.
The elevator could be requested at any floor at any time, going in
either direction.
floor: the floor that the elevator is being called to
direction: the direction the caller wants to go, up or down
"""
self._requests.insert(floor, direction)
if self._direction is None:
if floor > self.callbacks.current_floor:
self._direction = UP
elif floor < self.callbacks.current_floor:
self._direction = DOWN
def on_floor_selected(self, floor):
"""
This is called when somebody on the elevator chooses a floor.
This could happen at any time, whether or not the elevator is moving.
Any floor could be requested at any time.
floor: the floor that was requested
"""
if self._direction == UP and floor <= self.callbacks.current_floor:
print('select ignored:', floor)
return
if self._direction == DOWN and floor >= self.callbacks.current_floor:
print('select ignored:', floor)
return
self._requests.insert(floor)
if self._direction is None:
if floor > self.callbacks.current_floor:
self._direction = UP
elif floor < self.callbacks.current_floor:
self._direction = DOWN
def on_floor_changed(self):
"""
This lets you know that the elevator has moved one floor up or down.
You should decide whether or not you want to stop the elevator.
"""
assert(self.callbacks.motor_direction in (UP, DOWN))
floor = self.callbacks.current_floor
maximum = self._requests.is_max(floor, self._direction)
member = self._requests.is_member(floor, self._direction)
if maximum or member:
self.callbacks.motor_direction = None
if maximum and not member:
self.change_direction()
def on_ready(self):
"""
This is called when the elevator is ready to go.
Maybe passengers have embarked and disembarked. The doors are closed,
time to actually move, if necessary.
"""
assert(self.callbacks.motor_direction is None)
floor = self.callbacks.current_floor
if self._direction:
self._requests.delete(floor, self._direction)
if self._requests.is_empty():
self._direction = None
assert(self.callbacks.motor_direction is None)
elif self._requests.is_max(floor, self._direction):
self.change_direction()
assert(self.callbacks.motor_direction is None)
if self._requests.is_member(floor, self._direction):
self._requests.delete(floor, self._direction)
else:
self.callbacks.motor_direction = self._direction
else:
self.callbacks.motor_direction = self._direction
def change_direction(self):
assert(self._direction in (UP, DOWN))
if self._direction is UP:
self._direction = DOWN
elif self._direction is DOWN:
self._direction = UP
