python的修饰器版singleton模式
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
| #!/usr/bin/env python
# -*- coding: UTF-8 -*-
def singleton(cls):
'''
singleton 模式的修饰器，保留第一次初始化的值
例：
@singleton
class Class:
def __init__(self, v):
self.val = v
a = Class('a')
b = Class('b')
则b.val == 'a'
a is b返回True
'''
instance_container = []
def get_instance(*arg, **args):
if not len(instance_container):
instance_container.append(cls(*arg, **args))
return instance_container[0]
return get_instance
|