单例 对类变量的修改 批修改

#!python# -*- coding:utf-8 -*-# 场景：# 目的：通过单例实现客户端调用sdk时,sdk中的方法对客户端数据的批处理

# 参考：# {# Python单例模式(Singleton)的N种实现 - 知乎# https://zhuanlan.zhihu.com/p/37534850

# 设计模式(Python)-单例模式 - 简书# https://www.jianshu.com/p/ec6589e02e2f

# http://xiaorui.cc/2016/04/10/python多线程下保持单例模式的实例唯一/

# PythonDecoratorLibrary - Python Wiki# https://wiki.python.org/moin/PythonDecoratorLibrary

# 3. Data model — Python 3.7.3 documentation# https://docs.python.org/3/reference/datamodel.html#object.__new__

# 8.10. Queue — A synchronized queue class — Python 2.7.16 documentation# https://docs.python.org/2/library/queue.html# The Queue class in this module implements all the required locking semantics.

# 3. Data model — Python 3.7.3 documentation# https://docs.python.org/3/reference/datamodel.html#specialnames

# 3. Data model — Python 3.7.3 documentation# https://docs.python.org/3/reference/datamodel.html#object.__del__

# }# 注意：# 线程安全# 实例析构、类的析构

# 需要测试：# 1、线程安全# 2、效率

# TODO 类的析构

import threading

def make_synchronized(func):    func.__lock__ = threading.Lock()

    def synced_func(*args, **kws):        with func.__lock__:            return func(*args, **kws)

    return synced_func

class SdkSingletonBatchHandler(object):    __instance = None    # 存放批处理的队列 批处理方法对其按照先进先出FIFO处理    queue_ = []    queueLength = None    batchHandlerFunc = None    # 队列生存时间    timeToLiveSeconds = 1    __bornTime = 0

    @make_synchronized    def __new__(cls, *args, **kwargs):        if cls.__instance is None:            cls.__bornTime = time.time()            cls.__instance = object.__new__(cls, *args, **kwargs)        if cls.queueLength is None:            cls.queueLength = 10        if len(cls.queue_) >= cls.queueLength or cls.timeToLiveSeconds < time.time() - cls.__bornTime:            cls.batchHandler(cls.queue_)            cls.queue_ = []            cls.bornTime = time.time()        return cls.__instance

    @classmethod    def batchHandler(cls, queue_):        return cls.batchHandlerFunc

import time

def bizFuncNotBatch(param):    time.sleep(0.02)    print "do sth" + str(param)

def bizFuncBatch(param):    def batchHandler(paramList):        for i in paramList:            pass        time.sleep(0.02)        print "do sth" + str(paramList)

    s = SdkSingletonBatchHandler()    s.__class__.queueLength = 100    s.__class__.batchHandlerFunc = batchHandler    s.queue_.append(param)    print "do sth Batch"    # return 测试所需对象id    return s

# 测试# 线程安全

def testThreadSafeWorker():    s1 = bizFuncBatch("param")    s2 = bizFuncBatch("param")    print "id1={},id2={}".format(id(s1), id(s2))

task = []for i in range(300):    t = threading.Thread(target=testThreadSafeWorker())    task.append(t)for i in task:    i.start()for i in task:    i.join()

# 测试# 效率

data = [{‘i‘: i, ‘v‘: "value"} for i in range(1000)]consoleInfo = []consoleInfo.append("notBatch:Start:" + time.ctime())for i in data:    bizFuncNotBatch(i)consoleInfo.append("notBatch:End:" + time.ctime())consoleInfo.append("Batch:Start:" + time.ctime())for i in data:    bizFuncBatch(i)consoleInfo.append("Batch:End:" + time.ctime())for i in consoleInfo:    print i

class TestClassDel(object):    __instance = None

    def __init__(self):        print("init")

    def __new__(cls, *args, **kwargs):        if cls.__instance is None:            cls.__instance = object.__new__(cls, *args, **kwargs)        return cls.__instance

    def __del__(self):        print(1)

s1 = TestClassDel()s2 = TestClassDel()del s1del s2

init
init
1

Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] on win32

class TestClassDel(object):    __instance = None

    def __init__(self):        print "init"

    def __new__(cls, *args, **kwargs):        if cls.__instance is None:            cls.__instance = object.__new__(cls, *args, **kwargs)        return cls.__instance

    def __del__(self):        print 1

s1 = TestClassDel()s2 = TestClassDel()del s1del s2

Python 2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)] on win32

init
init

没有打印1

原文地址：https://www.cnblogs.com/yuanjiangw/p/11004727.html