# coding:utf-8

"""

property:负责把方法变成属性

"""

class Student(object):

    def get_score(self):

        return self._score

    def set_score(self, score):

        if not isinstance(score, int):

            raise ValueError('score must be an instance!')

        if score<0 or score>100:

            raise ValueError('score must between 0--100!')

        self._score = score

s =Student()

s.set_score(60)

print s.get_score()

#s.set_score(200)

"""

下面的方法既能检查参数，又可以用类似属性这样简单的方式来访问类的变量

把一个getter方法变成属性，只需要加上@property.

此时@property本身又创建了另一个装饰器@score.setter，负责把一个setter方法变成属性赋值

"""

class Student2(object):

    @property

    def score(self):

        return self._score

    @score.setter

    def score(self, score):

        if not isinstance(score, int):

            raise ValueError('score must be an instance!')

        if score<0 or score>100:

            raise ValueError('score must between 0--100!')

        self._score = score

s = Student2()

s.score =50

print s.score

#s.score = 120

"""

利用@property定义只读属性，只定义getattr，不定义setattr即可

"""

class Student3(object):

    @property

    def birth(self):

        return self._birth

    @birth.setter

    def birth(self,value):

        self._birth = value

    @property

    def age(self):

        return 2016 -  self._birth

s = Student3()

s.birth = 1988

print s.birth

print s.age