python面向对象之依赖注入

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# 组合
# a = a()
# b = b(a)
# c = c(b)
# d = d(c)

#依赖注入

class Mapper:
    __mapper_relation = {}

    @staticmethod
def register(cls,value):
        Mapper.__mapper_relation[cls]=value

    @staticmethod
def exist(cls):
        if cls in Mapper.__mapper_relation:
            return True
        return  False

@staticmethod
def value(cls):
        return  Mapper.__mapper_relation[cls]



class MyType(type):
    def __call__(cls, *args, **kwargs):
        obj = cls.__new__(cls,*args,**kwargs)
        arg_list = list(args)
        if Mapper.exist(cls):
            value = Mapper.value(cls)
            arg_list.append(value)
        obj.__init__(*arg_list,**kwargs)
        return obj

class Foo(metaclass=MyType):
    def __init__(self,name):
        self.name=name

    def f1(self):
        print(self.name)

class Bar(metaclass=MyType):
    def __init__(self, name):
        self.name = name

    def f1(self):
        print(self.name)

#解释器解释
#1，遇到class Foo，执行type的__init__方法
#2，Type的init的方法里面做什么呢？不知道 C语言写的 无法修改
#3，执行Type的__call__方法
# 执行Foo类的__new__方法
# 执行Foo类的__init__方法

Mapper.register(Foo,"foo_123")
Mapper.register(Bar,"bar_123")

obj = Foo()
print(obj.name)
obj2 = Bar()
print(obj2.name)

C:\Python35\python.exe D:/py_django/test/a3.py
foo_123
bar_123

Process finished with exit code 0

#!/usr/bin/env python
# -*- coding: utf-8 -*-

#依赖注入

class Mapper:
    __mapper_relation = {}

    @staticmethod
def register(cls,value):
        Mapper.__mapper_relation[cls]=value

    @staticmethod
def exist(cls):
        if cls in Mapper.__mapper_relation:
            return True
        return  False

@staticmethod
def value(cls):
        return  Mapper.__mapper_relation[cls]



class MyType(type):
    def __call__(cls, *args, **kwargs):
        obj = cls.__new__(cls,*args,**kwargs)
        arg_list = list(args)
        if Mapper.exist(cls):
            value = Mapper.value(cls)
            arg_list.append(value)
        obj.__init__(*arg_list,**kwargs)
        return obj


class BarFoo_parent:
    def __init__(self):
        pass

class Foo(metaclass=MyType):
    def __init__(self,name):
        self.name=name

    def f1(self):
        print(self.name)

class Bar(metaclass=MyType):
    def __init__(self, name):
        self.name = name

    def f1(self):
        print(self.name)

#解释器解释
#1，遇到class Foo，执行type的__init__方法
#2，Type的init的方法里面做什么呢？不知道 C语言写的 无法修改
#3，执行Type的__call__方法
# 执行Foo类的__new__方法
# 执行Foo类的__init__方法

Mapper.register(Foo,BarFoo_parent())
Mapper.register(Bar,Foo())

obj2 = Bar()
print(obj2)
print(obj2.name)
print(obj2.name.name)

C:\Python35\python.exe D:/py_django/test/a4.py
<__main__.Bar object at 0x0000000000714710>
<__main__.Foo object at 0x00000000007146D8>
<__main__.BarFoo_parent object at 0x0000000000714630>

Process finished with exit code 0