具有初始化的类实例,我需要共享此实例数据和线程之间的所有方法,但是一个变量,以在所有线程之间具有不同的结果,但要利用初始化的数据。我需要实例指向"私有"变量的所有类方法。
class A():
def __init__(self):
self.init_data = self._initialize() <- same for each thread
self.a = 0 <- private for each thread
def _initialize(self):
# Get data from db (high cost)
def calculate_a(self, data):
# Calculate 'a' result from init_data to private 'a' variable
class ThreadClass(threading.Thread):
# Inheritance?
# Pass instance as a init parameter and change somehow 'a' variable pointer?
a = A()
t1 = ThreadClass(a)
t2 = ThreadClass(a)
t1.start()
t2.start()
t1.calculate_a(data1)
t2.calculate_a(data2)
t1.a <- some result1
t2.a <- some result2
可能吗?有人可以给我任何有效的解决方案吗?
做到这一点的一种方法是创建一个从a继承的新类,并以昂贵的 init_data
作为类属性。这是从您的代码中得出的简短演示。
class A:
def __init__(self):
self.init_data = self._initialize() # <- same for each thread
self.a = 0 # <- private for each thread
def _initialize(self):
# Get data from db (high cost)
print('_initialize called')
return 1000
def calculate_a(self, data):
# Calculate 'a' result from init_data to private 'a' variable
self.a += self.init_data + data
class MyA(A):
# Create a single instance of the original class and store its
# init_data as a class attribute of MyA
init_data = A().init_data
# Get rid of the inherited _initialize method
_initialize = None
# Override the inherited __init__
def __init__(self):
self.a = 0
# Test
b = MyA()
b.calculate_a(10)
print(b.a)
c = MyA()
c.calculate_a(100)
print(c.a)
b.calculate_a(20)
print(b.a)
输出
_initialize called
1010
1100
2030
如您所见,A._initialize()
仅在定义MyA
类时被调用一次。MyA
的所有实例共享MyA.init_data
,MyA
的任何方法(包括它从A
继承的方法(都将在引用self.init_data
时使用该MyA.init_data
。