iterator

README

Golang Iterator

一、简介

Golang迭代器模式的定义与实现，用于在一些适合迭代器的场景使用。

二、安装

go get -u github.com/golang-infrastructure/go-iterator

三、Example

slice := []int{1, 2, 3, 4, 5}
iterator := NewSliceIterator(slice)
toSlice := ToSlice[int](iterator)
assert.Equal(t, slice, toSlice)

四、API

Iterator[T any]

// Iterator 表示一个迭代器，迭代器的元素类型是T
type Iterator[T any] interface {

	// Next 将迭代器的指针往后移动一个，同时返回指针当前指向的位置是否有元素
	Next() bool

	// Value 返回指针指向的元素，如果没有元素的话返回对应类型的零值
	Value() T
}

IteratorWithIndex[T any]

IteratorWithKey[T any]

ChainIterator[T any]

用来把多个迭代器组合为一个：

	iteratorA := NewRangeIterator(0, 5)
	iteratorB := NewRangeIterator(5, 10)

	iterator := NewChainIterator[int](iteratorA, iteratorB)
	slice := ToSlice[int](iterator)
	t.Log(slice)

ChannelIterator[T any]

用来把channel封装为迭代器：

	channel := make(chan int, 3)
	channel <- 1
	channel <- 2
	channel <- 3
	close(channel)

	iterator := NewChannelIterator(channel)
	slice := ToSlice[int](iterator)
	t.Log(slice)

CycleIterator[T any]

用来无限循环返回某个序列：

	iterator := NewCycleIterator(1, 2, 3)
	for i := 0; i < 100 && iterator.Next(); i++ {
		t.Log(iterator.Value())
	}

MapIterator[K comparable, V any]

用来迭代Map：

	m := make(map[string]int, 0)
	m["a"] = 1
	m["b"] = 2
	m["c"] = 3
	iterator := NewMapIterator(m)
	slice := ToSlice[*MapEntry[string, int]](iterator)
	t.Log(slice)

RangeIterator

用来返回一个范围：

	begin := -100
	end := 100
	iterator := NewRangeIterator(begin, end)
	slice := ToSlice[int](iterator)

	exceptedSlice := make([]int, 0)
	for begin < end {
		exceptedSlice = append(exceptedSlice, begin)
		begin++
	}

	assert.Equal(t, exceptedSlice, slice)

SliceIterator[T any]

用来把切片包装为迭代器：

	slice := []int{1, 2, 3, 4, 5}
	iterator := NewSliceIterator(slice)
	toSlice := ToSlice[int](iterator)
	assert.Equal(t, slice, toSlice)

Documentation

Index

• Variables
• func DoIterator[T any](iterator Iterator[T], iteratorFunc func(value T) bool)
• func IsIterator[T any](structObject any) bool
• func ToChannel[T any](iterator Iterator[T]) chan T
• func ToSlice[T any](iterator Iterator[T]) []T
• type ChainIterator
  • func NewChainIterator[T any](iterators ...Iterator[T]) *ChainIterator[T]
  • func (x *ChainIterator[T]) Next() bool
  • func (x *ChainIterator[T]) Value() T
• type ChannelIterator
  • func NewChannelIterator[T any](channel <-chan T) *ChannelIterator[T]
  • func (x *ChannelIterator[T]) Next() bool
  • func (x *ChannelIterator[T]) Value() T
• type CycleIterator
  • func NewCycleIterator[T any](slice ...T) *CycleIterator[T]
  • func (x *CycleIterator[T]) Next() bool
  • func (x *CycleIterator[T]) Value() T
• type Iterable
• type Iterator
  • func CastToIterator[T any](structObject any) (Iterator[T], error)
  • func FromChannel[T any](channel <-chan T) Iterator[T]
  • func FromSlice[T any](slice []T) Iterator[T]
• type IteratorWithIndex
• type IteratorWithKey
• type MapEntry
  • func (x *MapEntry[K, V]) GetKey() K
  • func (x *MapEntry[K, V]) GetValue() V
• type MapIterator
  • func NewMapIterator[K comparable, V any](m map[K]V) *MapIterator[K, V]
  • func (x *MapIterator[K, V]) Next() bool
  • func (x *MapIterator[K, V]) Value() *MapEntry[K, V]
• type RangeIterator
  • func NewRangeIterator(begin, end int) *RangeIterator
  • func (x *RangeIterator) Next() bool
  • func (x *RangeIterator) Value() int
• type ReverseIteratorWithIndex
• type ReverseIteratorWithKey
• type SliceIterator
  • func NewSliceIterator[T any](slice []T) *SliceIterator[T]
  • func (x *SliceIterator[T]) Next() bool
  • func (x *SliceIterator[T]) Value() T

Variables

var ErrIsNotIterator = errors.New("is not iterator")

Functions

func DoIterator

func DoIterator[T any](iterator Iterator[T], iteratorFunc func(value T) bool)

DoIterator 遍历一个迭代器

func IsIterator

func IsIterator[T any](structObject any) bool

IsIterator 判断给定的struct是否实现了迭代器

func ToChannel

func ToChannel[T any](iterator Iterator[T]) chan T

ToChannel 把迭代器转为channel

func ToSlice

func ToSlice[T any](iterator Iterator[T]) []T

ToSlice 把迭代器转为切片

Types

type ChainIterator

type ChainIterator[T any] struct {
	// contains filtered or unexported fields
}

ChainIterator 把多个迭代器组合为一个迭代器，

func NewChainIterator

func NewChainIterator[T any](iterators ...Iterator[T]) *ChainIterator[T]

func (*ChainIterator[T]) Next

func (x *ChainIterator[T]) Next() bool

func (*ChainIterator[T]) Value

func (x *ChainIterator[T]) Value() T

type ChannelIterator

type ChannelIterator[T any] struct {
	// contains filtered or unexported fields
}

ChannelIterator 用于把一个channel封装为iterator

func NewChannelIterator

func NewChannelIterator[T any](channel <-chan T) *ChannelIterator[T]

func (*ChannelIterator[T]) Next

func (x *ChannelIterator[T]) Next() bool

func (*ChannelIterator[T]) Value

func (x *ChannelIterator[T]) Value() T

type CycleIterator

type CycleIterator[T any] struct {
	// contains filtered or unexported fields
}

CycleIterator 把一个给定的序列无限循环

func NewCycleIterator

func NewCycleIterator[T any](slice ...T) *CycleIterator[T]

func (*CycleIterator[T]) Next

func (x *CycleIterator[T]) Next() bool

func (*CycleIterator[T]) Value

func (x *CycleIterator[T]) Value() T

type Iterable

type Iterable[T any] interface {

	// Iterator 返回当前对象的迭代器
	Iterator() Iterator[T]
}

Iterable 用于表示是可迭代的，拥有一个Iterator方法，调用时返回一个迭代器

type Iterator

type Iterator[T any] interface {

	// Next 将迭代器的指针往后移动一个，同时返回指针当前指向的位置是否有元素
	Next() bool

	// Value 返回指针指向的元素，如果没有元素的话返回对应类型的零值
	Value() T
}

Iterator 表示一个迭代器，迭代器的元素类型是T

func CastToIterator

func CastToIterator[T any](structObject any) (Iterator[T], error)

CastToIterator 转换为迭代器

func FromChannel

func FromChannel[T any](channel <-chan T) Iterator[T]

func FromSlice

func FromSlice[T any](slice []T) Iterator[T]

type IteratorWithIndex

type IteratorWithIndex[T any] interface {
	Iterator[T]
	Index() int
	Begin()
	First() bool
	NextTo(func(index int, value T) bool) bool
}

type IteratorWithKey

type IteratorWithKey[T any] interface {
	Iterator[T]
	Key() T
	Begin()
	First() bool
	NextTo(func(key T, value T) bool) bool
}

type MapEntry

type MapEntry[K, V any] struct {
	Key   K
	Value V
}

func (*MapEntry[K, V]) GetKey

func (x *MapEntry[K, V]) GetKey() K

func (*MapEntry[K, V]) GetValue

func (x *MapEntry[K, V]) GetValue() V

type MapIterator

type MapIterator[K comparable, V any] struct {
	// contains filtered or unexported fields
}

MapIterator 用于遍历一个Map的迭代器

func NewMapIterator

func NewMapIterator[K comparable, V any](m map[K]V) *MapIterator[K, V]

func (*MapIterator[K, V]) Next

func (x *MapIterator[K, V]) Next() bool

func (*MapIterator[K, V]) Value

func (x *MapIterator[K, V]) Value() *MapEntry[K, V]

type RangeIterator

type RangeIterator struct {
	// contains filtered or unexported fields
}

RangeIterator 范围递增的迭代器

func NewRangeIterator

func NewRangeIterator(begin, end int) *RangeIterator

NewRangeIterator [begin, end)的左闭右开区间

func (*RangeIterator) Next

func (x *RangeIterator) Next() bool

func (*RangeIterator) Value

func (x *RangeIterator) Value() int

type ReverseIteratorWithIndex

type ReverseIteratorWithIndex[T any] interface {
	IteratorWithIndex[T]
	Prev() bool
	End()
	Last() bool
	PrevTo(func(index int, value interface{}) bool) bool
}

type ReverseIteratorWithKey

type ReverseIteratorWithKey[T any] interface {
	IteratorWithKey[T]
	Prev() bool
	End()
	Last() bool
	PrevTo(func(key interface{}, value interface{}) bool) bool
}

type SliceIterator

type SliceIterator[T any] struct {
	// contains filtered or unexported fields
}

SliceIterator 用于把切片封装为迭代器

func NewSliceIterator

func NewSliceIterator[T any](slice []T) *SliceIterator[T]

func (*SliceIterator[T]) Next

func (x *SliceIterator[T]) Next() bool

func (*SliceIterator[T]) Value

func (x *SliceIterator[T]) Value() T