Python使用设计模式中的责任链模式与迭代器模式的示例

责任链模式

责任链模式：将能处理请求的对象连成一条链，并沿着这条链传递该请求，直到有一个对象处理请求为止，避免请求的发送者和接收者之间的耦合关系。

#encoding=utf-8 
# 
#by panda 
#职责连模式 
 
def printInfo(info): 
  print unicode(info, 'utf-8').encode('gbk') 
 
#抽象职责类 
class Manager(): 
  successor = None 
  name = '' 
  def __init__(self, name): 
    self.name = name 
   
  def SetSuccessor(self, successor): 
    self.successor = successor 
   
  def HandleRequest(self, request): 
    pass 
 
#具体职责类：经理 
class CommonManager(Manager): 
  def HandleRequest(self, request): 
    if request.RequestType == '请假' and request.Number <= 2: 
      printInfo('%s:%s 数量%d 被批准' % (self.name, request.RequestContent, request.Number)) 
    else: 
      if self.successor != None: 
        self.successor.HandleRequest(request) 
         
#具体职责类：总监 
class Majordomo(Manager): 
  def HandleRequest(self, request): 
    if request.RequestType == '请假' and request.Number <= 5: 
      printInfo('%s:%s 数量%d 被批准' % (self.name, request.RequestContent, request.Number)) 
    else: 
      if self.successor != None: 
        self.successor.HandleRequest(request) 
 
#具体职责类：总经理 
class GeneralManager(Manager): 
  def HandleRequest(self, request): 
    if request.RequestType == '请假': 
      printInfo('%s:%s 数量%d 被批准' % (self.name, request.RequestContent, request.Number)) 
    elif request.RequestType == '加薪' and request.Number <= 500: 
      printInfo('%s:%s 数量%d 被批准' % (self.name, request.RequestContent, request.Number)) 
    elif request.RequestType == '加薪' and request.Number > 500: 
      printInfo('%s:%s 数量%d 再说吧' % (self.name, request.RequestContent, request.Number)) 
 
class Request(): 
  RequestType = '' 
  RequestContent = '' 
  Number = 0 
 
def clientUI(): 
  jinLi = CommonManager('金力') 
  zongJian = Majordomo('宗健') 
  zhongJingLi = GeneralManager('钟金利') 
   
  jinLi.SetSuccessor(zongJian) 
  zongJian.SetSuccessor(zhongJingLi) 
   
  request = Request() 
  request.RequestType = '请假' 
  request.RequestContent = '小菜请假' 
  request.Number = 1 
  jinLi.HandleRequest(request) 
   
  request.RequestType = '请假' 
  request.RequestContent = '小菜请假' 
  request.Number = 5 
  jinLi.HandleRequest(request) 
   
  request.RequestType = '加薪' 
  request.RequestContent = '小菜要求加薪' 
  request.Number = 500 
  jinLi.HandleRequest(request) 
   
  request.RequestType = '加薪' 
  request.RequestContent = '小菜要求加薪' 
  request.Number = 1000 
  jinLi.HandleRequest(request) 
  return 
 
if __name__ == '__main__': 
  clientUI(); 

类图：

迭代器模式
迭代器模式：提供一种方法顺序访问一个聚合对象中的各个元素，而又不暴露该对象的内部表示。

python内置支持这种模式，所以一般来说，不用自己写，

#encoding=utf-8 
# 
#by panda 
#迭代器(Iterator)模式 
 
def printInfo(info): 
  print unicode(info, 'utf-8').encode('gbk') 
 
#迭代器抽象类 
class Iterator: 
  def First(self): 
    pass 
   
  def Next(self): 
    pass 
   
  def IsDone(self): 
    pass 
   
  def CurrentItem(self): 
    pass 
   
#集合抽象类 
class Aggregate: 
  def CreateIterator(self): 
    pass 
   
#具体迭代器类： 
class ConcreteIterator(Iterator): 
  aggregate = None 
  current = 0 
  def __init__(self, aggregate): 
    self.aggregate = aggregate 
    self.current = 0 
   
  def First(self): 
    return self.aggregate[0] 
 
  def Next(self): 
    ret = None 
    self.current += 1 
    if(self.current < len(self.aggregate)): 
      ret = self.aggregate[self.current] 
    return ret 
 
  def IsDone(self): 
    if(self.current < len(self.aggregate)): 
      return False 
    else: 
      return True 
 
  def CurrentItem(self): 
    ret = None 
    if(self.current < len(self.aggregate)): 
      ret = self.aggregate[self.current] 
    return ret 
   
#具体集合类 
class ConcreteAggregate(Aggregate): 
  items = None 
  def __init__(self): 
    self.items = []     
   
def clientUI(): 
  a = ConcreteAggregate() 
  a.items.append('大鸟') 
  a.items.append('小菜') 
  a.items.append('行李') 
  a.items.append('老外') 
  a.items.append('公交内部员工') 
  a.items.append('小偷') 
   
   
  printInfo('---------迭代器模式-------------') 
  i = ConcreteIterator(a.items) 
  item = i.First() 
  while(False == i.IsDone()): 
    printInfo("%s 请买车票！" % i.CurrentItem()); 
    i.Next() 
     
  printInfo('\n---------python内部迭代-------------') 
  for item in a.items: 
    printInfo("%s 请买车票！" % item); 
  return 
 
if __name__ == '__main__': 
  clientUI(); 

类图：

以上就是Python使用设计模式中的责任链模式与迭代器模式的示例。不积跬步，无以至千里；不积小流，无以成江海。的意思是说千里之路，是靠一步一步地走出来的，没有小步的积累，是不可能走完千里之途的。引申开来，就是做事要脚踏实地，一步一个脚印，不畏艰难，不怕曲折，坚忍不拔地干下去，才能最终达到目的。更多关于Python使用设计模式中的责任链模式与迭代器模式的示例请关注haodaima.com其它相关文章！