结构型
类与类之间 关系的一种模式
适配器模式
- 将一个类的接口转换成另一种接口。兼容。
俩种方式
- 多继承
# 银行支付和网上支付不一样
class BankPayment:
def cost(self, money):
print("银行支付")
# 继承网上支付。
class NewBankPayment(Payment, BankPayment):
def pay(self, money):
self.cost(money)
- 组合
class PaymentAdapter(Payment):
def __init__(self, payment):
self.payment = payment
def pay(self, money):
self.payment.cost(money)
桥模式
将一个事物的俩个维度分离，使其都可以独立地变化
形状和颜色
# 颜色和形状紧密耦合
class Shape:
pass
class Line(Shape):
pass
class Rectangle(Shape):
pass
class Circle(Shape):
pass
# 类爆炸 3 * 3 。
class RedLine(Line):
# * 3
pass
class RedRectangle(Rectangle):
# * 3
pass
改进后。
互相拥有
from abc import ABCMeta, abstractmethod
class Shape(metaclass=ABCMeta):
# 形状 拥有 color
def __init__(self, color):
self.color = color
@abstractmethod
def draw(self):
pass
class Color(metaclass=ABCMeta):
@abstractmethod
def paint(self, shape):
# color 调用 shape.
pass
class Line(Shape):
def draw(self):
self.color.paint(self)
class Rectangle(Shape):
def draw(self):
self.color.paint(self)
class Circle(Shape):
def draw(self):
self.color.paint(self)
class Red(Color):
def paint(self, shape):
print(" 红色的", shape)
class Green(Color):
def paint(self, shape):
print(" 绿色的", shape)
shape1 = Line(Red())
shape2 = Rectangle(Green())
shape1.draw()
shape2.draw()
组合模式
- 将对象组合成树形结构 以表示 部分-整体 的层次结构。单个对象和组合对象的使用具有一致性。
- 抽象组件、叶子组件、复合组件、客户端
- 部分和整体如何一致？使用统一的接口
from abc import ABCMeta,abstractmethod
class Graphic(metaclass=ABCMeta):
# 统一的接口
@abstractmethod
def draw(self):
pass
class Point(Graphic):
def __init__(self, x, y):
self.x = x
self.y = y
def draw(self):
print("Ponint:", self.x, self.y)
class Line(Graphic):
def __init__(self, p1, p2):
self.p1 = p1
self.p2 = p2
def draw(self):
print("Line:", self.p1, self.p2)
class Picture(Graphic):
# 复杂图形
def __init__(self, iterable):
self.children = []
for g in iterable:
self.children.append(g)
def draw(self):
for g in self.children:
g.draw()
p1 = Point(1,2)
p2 = Point(3,4)
l1 = Line(p1, p2)
pic = Picture([p1, p2, l1])
pic.draw()
外观模式
- 为子系统中的一组接口提供一个一致的界面。外观模式定义了一个高层接口，这个接口使得这子系统更加容易使用
- 外观 facade
- 子系统类 subsystem classes
# coding=utf-8
class Compute:
'外观类'
def __init__(self):
self.disk = Disk()
self.cpu = CPU()
self.memory = Memory()
def run(self):
self.disk.run()
self.cpu.run()
self.memory.run()
def stop(self):
self.disk.stop()
self.cpu.stop()
self.memory.stop()
class Disk:
# 子系统类
def run(self):
print("磁盘运行")
def stop(self):
print("磁盘停止")
class CPU:
def run(self):
print("CPU运行")
def stop(self):
print("CPU停止")
class Memory:
def run(self):
print("Memory运行")
def stop(self):
print("Memory停止")
c = Compute()
c.run()
c.stop()
代理模式
- 为其他对象提供一种代理以控制对这个对象的访问。
- 远程代理、虚代理、保护代理
from abc import ABCMeta,abstractmethod
class Subject(metaclass=ABCMeta):
# 为代理对象和真实对象提供统一的接口
@abstractmethod
def get_content(self):
pass
@abstractmethod
def set_content(self):
pass
class RealSubject(Subject):
def __init__(self, filename):
self.filename = filename
f = open(self.filename, 'r', encoding='utf-8')
self.content = f.read()
f.close()
def get_content(self):
return self.content
def set_content(self, content):
f = open(self.filename, 'w', encoding='utf-8')
f.write(content)
f.close()
class VirtualSubject(Subject):
# 虚代理
def __init__(self, filename):
self.filename = filename
self.subj = None
def get_content(self):
# 真正需要的时候才获取
if not self.subj:
self.subj = RealSubject(self.filename)
return self.subj.get_content()
def set_content(self, content):
if not self.subj:
self.subj = RealSubject(self.filename)
return self.subj.set_content(content)
class ProtectedSubject(Subject):
# 保护代理
def __init__(self, filename):
self.subj = RealSubject(filename)
def get_content(self):
return self.subj.get_content()
def set_content(self, content):
# 权限设置等
raise PermissionError("没权限")
subj = VirtualSubject('tree.py')
psubj = ProtectedSubject("tree.py")
psubj.set_content("dsafdsaf")
