FilesExpand file tree

 master

/

strategy.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

50 lines (36 loc) · 1.32 KB

 master

/

strategy.py

Copy path

Top

File metadata and controls

• Code
• Blame

50 lines (36 loc) · 1.32 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

#!/usr/bin/env python

# http://stackoverflow.com/questions/963965/how-is-this-strategy-pattern

# -written-in-python-the-sample-in-wikipedia

"""

In most of other languages Strategy pattern is implemented via creating some

base strategy interface/abstract class and subclassing it with a number of

concrete strategies (as we can see at

http://en.wikipedia.org/wiki/Strategy_pattern), however Python supports

higher-order functions and allows us to have only one class and inject

functions into it's instances, as shown in this example.

"""

import types

class StrategyExample:

def __init__(self, func=None):

self.name = 'Strategy Example 0'

if func is not None:

self.execute = types.MethodType(func, self)

def execute(self):

print(self.name)

def execute_replacement1(self):

print(self.name + ' from execute 1')

def execute_replacement2(self):

print(self.name + ' from execute 2')

if __name__ == '__main__':

strat0 = StrategyExample()

strat1 = StrategyExample(execute_replacement1)

strat1.name = 'Strategy Example 1'

strat2 = StrategyExample(execute_replacement2)

strat2.name = 'Strategy Example 2'

strat0.execute()

strat1.execute()

strat2.execute()

### OUTPUT ###

# Strategy Example 0

# Strategy Example 1 from execute 1

# Strategy Example 2 from execute 2