Python使用設計模式中的責任鏈模式與迭代器模式的示例

這篇文章主要介紹了Python使用設計模式中的責任鏈模式與迭代器模式的示例,責任鏈模式與迭代器模式都可以被看作為行為型的設計模式,需要的朋友可以參考下
責任鏈模式
責任鏈模式：將能處理請求的對象連成一條鏈，并沿著這條鏈傳遞該請求，直到有一個對象處理請求為止，避免請求的發送者和接收者之間的耦合關系。    
#encoding=utf-8
#
#by panda
#職責連模式
 
def printInfo(info):
  print unicode(info, 'utf-8').encode('gbk')
 
#抽象職責類
class Manager():
  successor = None
  name = ''
  def __init__(self, name):
    self.name = name
    
  def SetSuccessor(self, successor):
    self.successor = successor
    
  def HandleRequest(self, request):
    pass
 
#具體職責類：經理
class CommonManager(Manager):
  def HandleRequest(self, request):
    if request.RequestType == '請假' and request.Number <= 2:
      printInfo('%s:%s 數量%d 被批準' % (self.name, request.RequestContent, request.Number))
    else:
      if self.successor != None:
        self.successor.HandleRequest(request)
          
#具體職責類：總監
class Majordomo(Manager):
  def HandleRequest(self, request):
    if request.RequestType == '請假' and request.Number <= 5:
      printInfo('%s:%s 數量%d 被批準' % (self.name, request.RequestContent, request.Number))
    else:
      if self.successor != None:
        self.successor.HandleRequest(request)
 
#具體職責類：總經理
class GeneralManager(Manager):
  def HandleRequest(self, request):
    if request.RequestType == '請假':
      printInfo('%s:%s 數量%d 被批準' % (self.name, request.RequestContent, request.Number))
    elif request.RequestType == '加薪' and request.Number <= 500:
      printInfo('%s:%s 數量%d 被批準' % (self.name, request.RequestContent, request.Number))
    elif request.RequestType == '加薪' and request.Number > 500:
      printInfo('%s:%s 數量%d 再說吧' % (self.name, request.RequestContent, request.Number))
 
class Request():
  RequestType = ''
  RequestContent = ''
  Number = 0
 
def clientUI():
  jinLi = CommonManager('金力')
  zongJian = Majordomo('宗健')
  zhongJingLi = GeneralManager('鐘金利')
    
  jinLi.SetSuccessor(zongJian)
  zongJian.SetSuccessor(zhongJingLi)
    
  request = Request()
  request.RequestType = '請假'
  request.RequestContent = '小菜請假'
  request.Number = 1
  jinLi.HandleRequest(request)
    
  request.RequestType = '請假'
  request.RequestContent = '小菜請假'
  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();

類圖：

迭代器模式
迭代器模式：提供一種方法順序訪問一個聚合對象中的各個元素，而又不暴露該對象的內部表示。
python內置支持這種模式，所以一般來說，不用自己寫，    
#encoding=utf-8
#
#by panda
#迭代器(Iterator)模式
 
def printInfo(info):
  print unicode(info, 'utf-8').encode('gbk')
 
#迭代器抽象類
class Iterator:
  def First(self):
    pass
    
  def Next(self):
    pass
    
  def IsDone(self):
    pass
    
  def CurrentItem(self):
    pass
    
#集合抽象類
class Aggregate:
  def CreateIterator(self):
    pass
    
#具體迭代器類：
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
    
#具體集合類
class ConcreteAggregate(Aggregate):
  items = None
  def __init__(self):
    self.items = []     
    
def clientUI():
  a = ConcreteAggregate()
  a.items.append('大鳥')
  a.items.append('小菜')
  a.items.append('行李')
  a.items.append('老外')
  a.items.append('公交內部員工')
  a.items.append('小偷')
    
    
  printInfo('---------迭代器模式-------------')
  i = ConcreteIterator(a.items)
  item = i.First()
  while(False == i.IsDone()):
    printInfo("%s 請買車票！" % i.CurrentItem());
    i.Next()
      
  printInfo('\n---------python內部迭代-------------')
  for item in a.items:
    printInfo("%s 請買車票！" % item);
  return
 
if __name__ == '__main__':
  clientUI();
類圖：