Karim wrote:
Hello all,
I am seeking for information about the template pattern applied to python.
Could you explain some implementation or anything else? it would be
helpful.
Design patterns are means to an end, not an end in themselves. You
shouldn't say "I want to use the template pattern", you should say "I
want to solve this problem, what solution is appropriate?" and then only
use the template pattern if it is appropriate.
In any case, the template design pattern is one of the simpler design
patterns. Here's an example, adapted from Wikipedia's article on the
Template Method Pattern:
class AbstractGame:
"""An abstract class that is common to several games in which
players play against the others, but only one is playing at a
given time.
"""
def __init__(self, *args, **kwargs):
if self.__class__ is AbstractGame:
raise TypeError('abstract class cannot be instantiated')
def playOneGame(self, playersCount):
self.playersCount = playersCount
self.initializeGame()
j = 0
while not self.endOfGame():
self.makePlay(j)
j = (j + 1) % self.playersCount
self.printWinner()
def initializeGame(self):
raise TypeError('abstract method must be overridden')
def endOfGame(self):
raise TypeError('abstract method must be overridden')
def makePlay(self, player_num):
raise TypeError('abstract method must be overridden')
def printWinner(self):
raise TypeError('abstract method must be overridden')
Now to create concrete (non-abstract) games, you subclass AbstractGame
and override the abstract methods.
class Chess(AbstractGame):
def initializeGame(self):
# Put the pieces on the board.
...
def makePlay(player):
# Process a turn for the player
...
etc.
--
Steven
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