设计模式之迭代子模式

1类图

2python示例

'''
Created on 2017-2-10

@author: admin
'''
from _overlapped import NULL
from abc import abstractmethod
class AbstractList:
    @abstractmethod
    def add(self,item):pass
    @abstractmethod
    def len(self):pass
    @abstractmethod
    def item(self,index):pass
    @abstractmethod
    def iterator(self):pass
class MyList(AbstractList):
    def __init__(self,data=NULL):
        if(data==NULL):
            self.data=[];
        else:
            self.data=data;
    def add(self,item):
        self.data.append(item)
    def len(self):
        return len(self.data)
    def item(self,index):
        return self.data[index]
    def iterator(self):
        return Iterator(self);
class AbstractIterator:
    @abstractmethod
    def hasNext(self):pass
    @abstractmethod
    def next(self):pass
    

class Iterator(AbstractIterator):
    def __init__(self,mylist):
        self.list=mylist;
        self.index=0;
        
    def hasNext(self):
        if self.index>=self.list.len():
            return False
        else:
            return True
    def next(self):
        if self.hasNext():
            data=self.list.item(self.index);
            self.index+=1;
            return data;
        else:
            raise Exception("index out of bound")
    
if __name__ == '__main__':
    mylist=MyList([1,2,3,4,5,6,7,8,9]);
    it=mylist.iterator();
    while it.hasNext():
        print(it.next(),end=",");