面向对象的设计模式2

结构型模式

　　■适配器模式

　　■组合模式

　　■代理模式

 

设计模式六大原则

　　■开放封闭原则

　　■里氏替换原则

　　■依赖倒置原则

　　■接口隔离原则

　　■迪米特法则

　　■单一职责原则

 

1.适配器模式

　　内容：将一个类的接口转化成客户希望的另一个接口。适配器模式使得原本有接口不兼容而不能一起工作的那些类可以一起工作

 

# coding : utf-8
# create by ztypl on 2017/5/25

from abc import abstractmethod, ABCMeta

class Payment(metaclass=ABCMeta):
    @abstractmethod
    def pay(self, money):
        raise NotImplementedError


class Alipay(Payment):
    def pay(self, money):
        print("支付宝支付%s元"%money)


class ApplePay(Payment):
    def pay(self, money):
        print("苹果支付%s元"%money)

#------待适配类------

class WechatPay:
    def huaqian(self, a, b):
        print("微信支付%s元"%(a+b))

#------类适配器------

class RealWeChatPay(Payment, WechatPay):
    def pay(self, money):
        return self.huaqian(money, 0)


#------对象适配器------
class PayAdapter(Payment):
    def __init__(self, payment):
        self.payment = payment

    def pay(self, money):
        return self.payment.huaqian(money, 0)


#RealWeChatPay().pay(100)
PayAdapter(WechatPay()).pay(1000)

 

　2.　组合模式

 

 

# coding : utf-8
# create by ztypl on 2017/5/25

from abc import abstractmethod, ABCMeta

class Graphic(metaclass=ABCMeta):
    @abstractmethod
    def draw(self):
        pass

    @abstractmethod
    def add(self, graphic):
        pass

    @abstractmethod
    def getchildren(self):
        pass


class Point(Graphic):
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def draw(self):
        print(self)

    def add(self, graphic):
        raise TypeError

    def getchildren(self):
        raise TypeError

    def __str__(self):
        return "点(%s, %s)" % (self.x, self.y)


class Line(Graphic):
    def __init__(self, p1, p2):
        self.p1 = p1
        self.p2 = p2

    def draw(self):
        print(self)

    def add(self, graphic):
        raise TypeError

    def getchildren(self):
        raise TypeError

    def __str__(self):
        return "线段[%s, %s]" % (self.p1, self.p2)


class Picture(Graphic):
    def __init__(self):
        self.children = []

    def add(self, graphic):
        self.children.append(graphic)

    def getchildren(self):
        return self.children

    def draw(self):
        print("------复合图形------")
        for g in self.children:
            g.draw()
        print("------END------")


pic1 = Picture()
pic1.add(Point(2,3))
pic1.add(Line(Point(1,2), Point(4,5)))
pic1.add(Line(Point(0,1), Point(2,1)))

pic2 = Picture()
pic2.add(Point(-2,-1))
pic2.add(Line(Point(0,0), Point(1,1)))

pic = Picture()
pic.add(pic1)
pic.add(pic2)

pic.draw()

3.代理模式

# coding : utf-8
# create by ztypl on 2017/5/26

from abc import ABCMeta, abstractmethod

class Subject(metaclass=ABCMeta):
    @abstractmethod
    def get_content(self):
        pass


class RealSubject(Subject):
    def __init__(self, filename):
        self.filename = filename
        print("读取%s文件内容"%filename)
        f = open(filename)
        self.content = f.read()
        f.close()

    def get_content(self):
        return self.content

    def set_content(self, content):
        f = open(self.filename, 'w')
        f.write(content)
        f.close()



class ProxyA(Subject):
    def __init__(self, filename):
        self.subj = RealSubject(filename)

    def get_content(self):
        return self.subj.get_content()


class ProxyB(Subject):
    def __init__(self, filename):
        self.filename = filename
        self.subj = None

    def get_content(self):
        if not self.subj:
            self.subj = RealSubject(self.filename)
        return self.subj.get_content()


class ProxyC(Subject):
    def __init__(self, filename):
        self.subj = RealSubject(filename)

    def get_content(self):
        return self.get_content()

    def set_content(self):
        raise PermissionError

    # 写一个set_content

b = ProxyB("abc.txt")
#print(b.get_content())