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：