python-patterns/command.py at master · cppfool/python-patterns

Repository navigation

#!/usr/bin/env python

# -*- coding: utf-8 -*-

import os

class MoveFileCommand(object):

def __init__(self, src, dest):

self.src = src

self.dest = dest

def execute(self):

print('renaming {} to {}'.format(self.src, self.dest))

os.rename(self.src, self.dest)

def undo(self):

print('renaming {} to {}'.format(self.dest, self.src))

os.rename(self.dest, self.src)

def main():

command_stack = []

# commands are just pushed into the command stack

command_stack.append(MoveFileCommand('foo.txt', 'bar.txt'))

command_stack.append(MoveFileCommand('bar.txt', 'baz.txt'))

# they can be executed later on

for cmd in command_stack:

cmd.execute()

# and can also be undone at will

for cmd in reversed(command_stack):

cmd.undo()

if __name__ == "__main__":

main()

### OUTPUT ###

# renaming foo.txt to bar.txt

# renaming bar.txt to baz.txt

# renaming baz.txt to bar.txt

# renaming bar.txt to foo.txt