Python迭代模式实例详解

# -*- coding: utf-8 -*-

"""

Created on Thu Mar 29 11:43:05 2018

@author: mz

"""

class Iterator(object):

    def Next(self):

        pass

    def HasNext(self):

        pass

    def First(self):

        pass

    def Forward(self):

        pass

class CocreteIterator(Iterator):

    def __init__(self, aggregate):

        self._aggregate = aggregate

    def Next(self):

        return self._aggregate.Next()

    def HasNext(self):

        return self._aggregate.HasNext()

    def First(self):

        return self._aggregate.First()

    def Forward(self):

        return self._aggregate.Forward()

class Aggregate(object):

    def CreateIterator(self):

        pass

    def Next(self):

        pass

    def HasNext(self):

        pass

    def First(self):

        pass

    def Attach(self, obj):

        pass

    def Forward(self):

        pass

class ConcreteAggregate(object):

    def __init__(self):

        self._lst = []

        self._index = 0

    def CreateIterator(self):

        return CocreteIterator(self)

    def Next(self):

        return self._lst[self._index]

    def HasNext(self):

        return self._index

    def First(self):

        self._index = 0

        return self._lst[0]

    def Attach(self, obj):

        self._lst.append(obj)

    def Forward(self):

        self._index += 1

if "__main__" == __name__:

    aggregate = ConcreteAggregate()

    aggregate.Attach(1)

    aggregate.Attach("2")

    aggregate.Attach("a")

    aggregate.Attach("b")

    aggregate.Attach("c")

    aggregate.Attach("45")

    it = aggregate.CreateIterator()

    while it.HasNext():

        print(it.Next())

        it.Forward()