设计模式中的原型模式在Python程序中的应用示例
原型模式：
原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。
原型模式本质就是克隆对象，所以在对象初始化操作比较复杂的情况下，很实用，能大大降低耗时，提高性能，因为“不用重新初始化对象，而是动态地获得对象运行时的状态”。
应用特性：
需要大量的基于某个基础原型进行微量修改而得到新原型时使用。
结构特性：
对象的复制机制，即浅复制和深复制。
例1：
#!/usr/bin/env python
#encoding: utf-8
from copy import copy, deepcopy
class test_obj:
def __init__(self, id):
self.id = id
class proto_type:
def __init__(self, name, id):
self.name = name
self.obj = test_obj(id)
def display(self):
print self.name
print self.obj.id
def clone(self):
return copy(self)
def deep_clone(self):
return deepcopy(self)
if '__main__' == __name__:
obj1 = proto_type('name1', 1)
obj2 = obj1.clone()
obj3 = obj1.deep_clone()
obj2.name = 'name2'
obj2.obj.id = 2
obj3.name = 'name3'
obj3.obj.id = 3
obj1.display()
obj2.display()
obj3.display()
print obj1.__class__
print obj2.__class__
print obj3.__class__
结果：
name1 2 #因为obj2是浅复制，所以对象没有被复制，导致新对象的修改影响了原来的就对象的值 name2 2 name3 3 #因为是深复制，所以不会影响之前的旧对象 __main__.proto_type __main__.proto_type __main__.proto_type
这里我们再来回顾一下Python编程基础中关于浅拷贝和深拷贝的知识点：
浅拷贝（Shallow Copy）:
指对象的字段被拷贝，而字段引用的对象不会被拷贝，拷贝的对象和源对象只是名称相同，但是他们共用一个实体。
深拷贝（deep copy）:
对对象实例中字段引用的对象也进行拷贝。
好了，基于以上，我们再来看一个例子：
例2：
#encoding=utf-8
#
#by panda
#原型模式
import copy
def printInfo(info):
print unicode(info, 'utf-8').encode('gbk')
#拷贝接口
class ICloneable:
def shallowClone(self):
return copy.copy(self)
def deepClone(self):
return copy.deepcopy(self)
#工作经历
class WorkExperience(ICloneable):
workData = ""
company = ""
pass
#简历
class Resume(ICloneable):
name = ""
sex = '未知'
age = 0
work = None
def __init__(self, name, work = WorkExperience()):
self.name = name
self.work = work;
def setPersonInfo(self, sex, age):
self.sex = sex
self.age = age
def setWorkExperience(self, workData, company):
self.work.workData = workData
self.work.company = company
def display(self):
printInfo('%s, %s, %d' % (self.name,self.sex,self.age))
printInfo('%s, %s' % (self.work.workData, self.work.company))
def clientUI():
a = Resume('大鸟')
a.setPersonInfo('男',29)
a.setWorkExperience("1998-2000","XX公司")
#浅拷贝
b = a.shallowClone()
b.setWorkExperience("2000-2006","YY公司")
#深拷贝
c = a.deepClone()
c.setWorkExperience("2006-2009","ZZ公司")
b.display()
a.display()
c.display()
return
if __name__ == '__main__':
clientUI();
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