go语言中数据接口set集合的实现

package main

import (
	"errors"
	"fmt"
	"sync"
)

/*
用map实现一个线程安全的set
*/

type void struct{}

var member void

type IData interface{}

type Set struct {
	mapset map[IData]struct{}
	mutex  sync.Mutex
}

func NewSet() *Set {
	return &Set{
		mapset: make(map[IData]struct{}),
		mutex:  sync.Mutex{},
	}
}

func (s *Set) Add(data IData) bool {
	s.mutex.Lock()
	defer s.mutex.Unlock()
	s.mapset[data] = member
	return true
}

func (s *Set) Remove(data IData) error {
	s.mutex.Lock()
	defer s.mutex.Unlock()
	for k, _ := range s.mapset {
		if k == data {
			delete(s.mapset, k)
			return nil
		}
	}
	return errors.New("not found")
}

func (s *Set) Pop() IData {
	s.mutex.Lock()
	defer s.mutex.Unlock()
	if len(s.mapset) <= 0 {
		return nil
	}
	for k, _ := range s.mapset {
		return s.mapset[k]
	}
	return nil
}

func (s *Set) Size() int {
	s.mutex.Lock()
	defer s.mutex.Unlock()
	return len(s.mapset)

}

func (s *Set) All() []IData {
	s.mutex.Lock()
	defer s.mutex.Unlock()
	datas := make([]IData, 0)
	for k, _ := range s.mapset {
		datas = append(datas, k)
	}
	return datas
}

func main() {
	// test
	myset := NewSet()
	myset.Add(1)
	myset.Add(2)
	myset.Add(1)
	fmt.Println(myset.All()) // [1 2]

	myset.Add(3)
	fmt.Println(myset.Size()) //3
	fmt.Println(myset.All())  // [1 2 3]

	myset.Remove(2)
	fmt.Println(myset.All()) // [1 2 3]

}

// sets.String is a set of strings, implemented via map[string]struct{} for minimal memory consumption.
// String类型定义，使用map来实现set集合，集合的元素是string
type String map[string]Empty

// NewString creates a String from a list of values.
// 构造一个set，set集合存放的值是string类型
func NewString(items ...string) String {
	ss := String{}
	ss.Insert(items...)
	return ss
}


// Insert adds items to the set.
// 插入元素到集合
func (s String) Insert(items ...string) String {
	for _, item := range items {
		s[item] = Empty{}
	}
	return s
}

// Delete removes all items from the set.
// 从set中删除指定string
func (s String) Delete(items ...string) String {
	for _, item := range items {
		delete(s, item)
	}
	return s
}

// Has returns true if and only if item is contained in the set.
// 判断set是否包含指定的string
func (s String) Has(item string) bool {
	_, contained := s[item]
	return contained
}

// HasAll returns true if and only if all items are contained in the set.
// 判断set是否包括一组所有的字符串
func (s String) HasAll(items ...string) bool {
	for _, item := range items {
		if !s.Has(item) {
			return false
		}
	}
	return true
}

// HasAny returns true if any items are contained in the set.
// 判断一组字符串是否有包括在set中
func (s String) HasAny(items ...string) bool {
	for _, item := range items {
		if s.Has(item) {
			return true
		}
	}
	return false
}