这样怎么样:
from collections import defaultdict
_items = defaultdict(set)
_owner = {}
class CanHaveItems(object):
@property
def items(self):
return iter(_items[self])
def take(self, item):
item.change_owner(self)
def lose(self, item):
""" local cleanup """
class _nobody(CanHaveItems):
def __repr__(self):
return '_nobody'
_nobody = _nobody()
class Destroyed(object):
def __repr__(self):
return 'This is an ex-item!'
class Item(object):
def __new__(cls, *a, **k):
self = object.__new__(cls)
_owner[self] = _nobody
_items[_nobody].add(self)
self._damage = .0
return self
def destroy(self):
self.change_owner(_nobody)
self.__class__ = Destroyed
@property
def damage(self):
return self._damage
@damage.setter
def damage(self, value):
self._damage = value
if self._damage >= 1.:
self.destroy()
def change_owner(self, new_owner):
old_owner = _owner[self]
old_owner.lose(self)
_items[old_owner].discard(self)
_owner[self] = new_owner
_items[new_owner].add(self)
class Ball(Item):
def __init__(self, color):
self.color = color
def __repr__(self):
return 'Ball(%s)' % self.color
class Player(CanHaveItems):
def __init__(self, name):
self.name = name
def __repr__(self):
return 'Player(%s)' % self.name
ball = Ball('red')
ball = Ball('blue')
joe = Player('joe')
jim = Player('jim')
print list(joe.items), ':', list(jim.items)
joe.take(ball)
print list(joe.items), ':', list(jim.items)
jim.take(ball)
print list(joe.items), ':', list(jim.items)
print ball, ':', _owner[ball], ':', list(jim.items)
ball.damage += 2
print ball, ':', _owner[ball], ':', list(jim.items)
print _items, ':', _owner