mirror of
https://github.com/crazybber/go-pattern-examples.git
synced 2024-11-24 20:56:03 +03:00
finish iterator pattern
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Edward
parent
eabae2e9b7
commit
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@ -4,8 +4,21 @@
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迭代器模式在各种语言中都有很深入，很广泛的应用，迭代器模式就是，对这种存在于语言中的基本模式的进一步应用。
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迭代器模式中的两个重要的接口：
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迭代器是一种管理数据的方式。
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```go
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type Iterator interface {
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//定义迭代器可以进行的动作
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Next()
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//...
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}
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type IEnumerator interface {
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//返回一个迭代器接口
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Iterator() Iterator
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}
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```
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迭代器是一种管理数据的方式,往往需要一个管理数据的内在容器/集合/链表/栈等结构，需要注意的是，一般在访问上不实现为链表的访问方式，而使用滑动游标的方式。
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现实生活中的景区的地图指南就是一个很好的迭代器的例子，地图就是一个迭代器，不论是哪个景区，都能通过一张地图(或者说这个迭代器)，让你明白当前景区的景点数，最佳参观顺序等，游客只需要按照迭代器的方式去访问景点即可。
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@ -3,55 +3,76 @@ package iterator
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////////////////////////////////
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//使用景点例子
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//ITouristMap 游客地图是一个迭代器Iterator，为用户提供当前景区中不同景点的统一访问能力
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type ITouristMap interface {
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FirstPot() //首个景点
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IsLastPot() bool //当前景点是否是最后一个
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Next() interface{} //下一个景点
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//Iterator 游客地图是一个迭代器Iterator，为用户提供当前景区中不同景点的统一访问能力
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type Iterator interface {
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Reset() //重置
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FirstPot() IPot //首个景点
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IsLastPot() bool //当前景点是否是最后一个
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Next() IPot //下一个景点
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}
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//IScenicArea 是一个针对景区的Aggregate聚合类型接口，返回一个迭代器接口
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//IScenicArea 返回一个游客访问接口
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type IScenicArea interface {
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Iterator() ITouristMap
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//IPot 景点对象的接口
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type IPot interface {
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Visit() //景点可以参观
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}
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//ScenicArea 景区包含所有的景点
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type ScenicArea struct {
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count int //景点的数量
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pots []interface{} //景点列表，景区可能一直在开发新的景点，所以景区的数量可能一直在增长
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count int //景点的数量
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pots []IPot //景点列表，景区可能一直在开发新的景点，所以景区的数量可能一直在增长
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}
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//Iterator 通过
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func (s *ScenicArea) Iterator() ITouristMap {
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return &ScenicAreaPotsMap{
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numbers: n,
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next: n.start,
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//PotsIterator 实现景区景点迭代器的对象
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//PotsIterator 该对象的目的就是为了隐藏景区本身
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//PotsIterator 实现为一个游标迭代器
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type PotsIterator struct {
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cursor int
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potsSlice []IPot
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}
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//Iterator 返回一个接待
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func (s *ScenicArea) Iterator() Iterator {
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return &PotsIterator{
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cursor: 0,
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potsSlice: s.pots,
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}
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}
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//ScenicAreaPotsMap 就是景区提供的迭代器类型，要实现具体的景区景点的迭代访问能力
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type ScenicAreaPotsMap struct {
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numbers *Numbers
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next int
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//AddPot 添加景点
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func (s *ScenicArea) AddPot(pots ...IPot) {
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for i := range pots {
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s.count++
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s.pots = append(s.pots, pots[i])
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}
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}
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//PotsCount 添加景点
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func (s *ScenicArea) PotsCount() int {
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return s.count
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}
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//Reset 重置
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func (s *PotsIterator) Reset() {
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s.cursor = 0
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}
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//FirstPot 第一个景点
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func (i *ScenicAreaPotsMap) FirstPot() {
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i.next = i.numbers.start
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func (s *PotsIterator) FirstPot() IPot {
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return s.potsSlice[0]
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}
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//IsLastPot 是否是最后一个
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func (i *ScenicAreaPotsMap) IsLastPot() bool {
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return i.next > i.numbers.end
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//IsLastPot 判断游标的位置
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func (s *PotsIterator) IsLastPot() bool {
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return s.cursor == -1
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}
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//Next 去路线上的下一个景点
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func (i *ScenicAreaPotsMap) Next() interface{} {
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if !i.IsDone() {
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next := i.next
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i.next++
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return next
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func (s *PotsIterator) Next() IPot {
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if s.cursor+1 == len(s.potsSlice) {
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s.cursor = -1 //设置到最后
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return nil
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}
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return nil
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s.cursor++
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return s.potsSlice[s.cursor]
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}
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@ -1,19 +1,52 @@
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package iterator
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func ExampleIterator() {
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var aggregate Aggregate
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aggregate = NewNumbers(1, 10)
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import (
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"fmt"
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"testing"
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)
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IteratorPrint(aggregate.Iterator())
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// Output:
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// 1
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// 2
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// 3
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// 4
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// 5
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// 6
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// 7
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// 8
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// 9
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// 10
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//ChildPot 儿童景点
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type ChildPot struct {
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Name string
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}
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func (c *ChildPot) Visit() {
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fmt.Println("i am: ", c.Name)
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}
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func TestIterator(t *testing.T) {
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scenicArea := ScenicArea{}
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scenicArea.AddPot(&ChildPot{Name: "monkey garden"}, &ChildPot{Name: "fairy country"}, &ChildPot{Name: "future space"})
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t.Log("pots count:", scenicArea.PotsCount())
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potInterator := scenicArea.Iterator()
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pot := potInterator.FirstPot()
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t.Logf("first pot: %#v\n", pot)
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VisitAllPots(potInterator)
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t.Log("add a pot", "pot: count", scenicArea.PotsCount())
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scenicArea.AddPot(&ChildPot{Name: "virtual world"})
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t.Log("pots count:", scenicArea.PotsCount())
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//切片变了，要重新获取
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potInterator = scenicArea.Iterator()
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potInterator.Reset()
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VisitAllPots(potInterator)
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}
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func VisitAllPots(i Iterator) {
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for c := i.FirstPot(); !i.IsLastPot(); c = i.Next() {
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c.Visit()
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fmt.Printf("finish visit pot : %#v\n", c)
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}
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}
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5
go.mod
5
go.mod
@ -2,4 +2,7 @@ module github.com/crazybber/go-fucking-algorithm
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go 1.14
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require github.com/logrusorgru/aurora v0.0.0-20200102142835-e9ef32dff381
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require (
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github.com/logrusorgru/aurora v0.0.0-20200102142835-e9ef32dff381
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go.uber.org/zap v1.15.0
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)
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42
go.sum
42
go.sum
@ -1,2 +1,44 @@
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github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
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github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
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github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
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github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
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github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
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github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
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github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
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github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
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github.com/logrusorgru/aurora v0.0.0-20200102142835-e9ef32dff381 h1:bqDmpDG49ZRnB5PcgP0RXtQvnMSgIF14M7CBd2shtXs=
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github.com/logrusorgru/aurora v0.0.0-20200102142835-e9ef32dff381/go.mod h1:7rIyQOR62GCctdiQpZ/zOJlFyk6y+94wXzv6RNZgaR4=
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github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
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github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
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github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
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github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
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github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
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github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
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go.uber.org/atomic v1.6.0 h1:Ezj3JGmsOnG1MoRWQkPBsKLe9DwWD9QeXzTRzzldNVk=
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go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
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go.uber.org/multierr v1.5.0 h1:KCa4XfM8CWFCpxXRGok+Q0SS/0XBhMDbHHGABQLvD2A=
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go.uber.org/multierr v1.5.0/go.mod h1:FeouvMocqHpRaaGuG9EjoKcStLC43Zu/fmqdUMPcKYU=
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go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=
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go.uber.org/zap v1.15.0 h1:ZZCA22JRF2gQE5FoNmhmrf7jeJJ2uhqDUNRYKm8dvmM=
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go.uber.org/zap v1.15.0/go.mod h1:Mb2vm2krFEG5DV0W9qcHBYFtp/Wku1cvYaqPsS/WYfc=
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golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
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golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
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golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
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golang.org/x/mod v0.0.0-20190513183733-4bf6d317e70e/go.mod h1:mXi4GBBbnImb6dmsKGUJ2LatrhH/nqhxcFungHvyanc=
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golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
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golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
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golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
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golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
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golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
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golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
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golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
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golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
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golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
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golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
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gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
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gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
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gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
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gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
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honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
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