344 lines
6.6 KiB
Plaintext
344 lines
6.6 KiB
Plaintext
package rank_util
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import (
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"sync"
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)
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// RankUtil
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// @description:排行工具类
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type RankUtil struct {
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// maxCount 排行榜最大数量
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maxCount int
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// compar 对比函数 返回含义 -1:a<b 0:a=b 1:a>b
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compar func(a, b interface{}) int
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// dataList 排行数据
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dataList []*Model
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// dataDict 数据字典
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dataDict map[string]*Model
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// dataLock 数据锁
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dataLock sync.RWMutex
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}
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// NewRankUtil
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// @description: 构造排行对象
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// parameter:
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// @mc:最大容量
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// @comp:元素比对方法
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// return:
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func NewRankUtil(mc int, comp func(a, b interface{}) int) *RankUtil {
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result := &RankUtil{
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maxCount: mc,
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compar: comp,
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dataList: make([]*Model, 0, mc),
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dataDict: make(map[string]*Model, mc),
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}
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return result
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}
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// GetMaxCount
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// @description: 获取排行榜最大数量
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// parameter:
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// @receiver r:
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// return:
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// @int:
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func (r *RankUtil) GetMaxCount() int {
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return r.maxCount
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}
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// GetCount
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// @description: 获取排行榜当前数量
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// parameter:
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// @receiver r:
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// return:
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// @int:
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func (r *RankUtil) GetCount() int {
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r.dataLock.RLock()
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defer r.dataLock.RUnlock()
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return len(r.dataList)
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}
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// IsFull
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// @description: 判断排行榜是否已经满了
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// parameter:
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// @receiver r:
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// return:
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// @bool:
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func (r *RankUtil) IsFull() bool {
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r.dataLock.RLock()
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defer r.dataLock.RUnlock()
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return len(r.dataList) == r.maxCount
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}
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// GetAll
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// @description: 获取排行榜内容
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// parameter:
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// @receiver r:
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// return:
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// @[]*Model:
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func (r *RankUtil) GetAll() []*Model {
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r.dataLock.RLock()
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defer r.dataLock.RUnlock()
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result := make([]*Model, 0, len(r.dataList))
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for _, item := range r.dataList {
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if item == nil || item.obj == nil {
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break
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}
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result = append(result, item)
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}
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return result
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}
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// GetRankListBySkip
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// @description: 获取排行榜内容
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// parameter:
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// @receiver r:
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// @skip:跳过的数量
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// @count:跳过后需要返回的数量
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// return:
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// @[]*Model:
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func (r *RankUtil) GetRankListBySkip(skip, count int) []*Model {
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r.dataLock.RLock()
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defer r.dataLock.RUnlock()
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result := make([]*Model, 0, count)
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cn := len(r.dataList)
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if skip >= cn {
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return result
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}
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for i := 0; i < count; i++ {
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item := r.dataList[skip+i]
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if item == nil || item.obj == nil {
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break
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}
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result = append(result, item)
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}
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return result
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}
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// GetItemForK
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// @description: 根据key获取对象
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// parameter:
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// @receiver r:
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// @k:key
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// return:
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// @*Model:
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func (r *RankUtil) GetItemForK(k string) *Model {
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r.dataLock.RLock()
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defer r.dataLock.RUnlock()
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item, _ := r.dataDict[k]
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return item
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}
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// GetItemForRank
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// @description: 根据排名获取对应对象
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// parameter:
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// @receiver r:
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// @rank:排名
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// return:
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// @*Model:
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func (r *RankUtil) GetItemForRank(rank int) *Model {
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r.dataLock.RLock()
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defer r.dataLock.RUnlock()
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if len(r.dataList) < rank {
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return nil
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}
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return r.dataList[rank-1]
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}
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// Refresh
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// @description: 刷新排行榜
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// parameter:
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// @receiver r:
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// @k:key
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// @o:排行持有的对象，业务层不应该持有该对象。否则业务层更改内容，会导致排行榜内容被改变
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// @isup:变动是否升高
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// return:
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// @changeRank:排行是否变动
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// @dm:如果有对象，因为排行变动导致掉出排行榜，则返回该对象，否则返回nil
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func (r *RankUtil) Refresh(k string, o interface{}, isup bool) (changeRank bool, dm *Model) {
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r.dataLock.Lock()
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defer r.dataLock.Unlock()
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changeRank = false
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curItem, exists := r.dataDict[k]
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if isup {
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if !exists {
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newRank := len(r.dataList) + 1
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curItem = &Model{rank: newRank, key: k, obj: o}
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// 排行榜未满，必定入榜，则先加入排行榜
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if newRank <= r.maxCount {
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r.dataList = append(r.dataList, curItem)
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r.dataDict[curItem.key] = curItem
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changeRank = true
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_, dm = r.upRank(curItem)
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} else {
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changeRank, dm = r.upRank(curItem)
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}
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} else {
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curItem.obj = o
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changeRank, dm = r.upRank(curItem)
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}
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} else {
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// 如果在排行榜内，从之前往下比较
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if exists {
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curItem.obj = o
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changeRank = r.downRank(curItem)
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} else {
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// 如果不在排行榜内，直接结束
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}
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}
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return
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}
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// Delete
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// @description: 删除k指定的对象,很耗性能，不建议高频使用
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// parameter:
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// @receiver r:
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// @k:key
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// return:
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// @bool:true:代表key存在排行榜中，并且删除成功 false:其他情况
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func (r *RankUtil) Delete(k string) bool {
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r.dataLock.Lock()
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defer r.dataLock.Unlock()
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m, exists := r.dataDict[k]
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if !exists {
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return false
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}
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//从当前位置向后移动，到最后的时候，删除
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for {
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if m.rank >= len(r.dataList) {
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break
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}
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am := r.dataList[m.rank]
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r.exchange(m, am)
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m = am
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}
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//最后一个应该是要删除的对象
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r.dataList = append(r.dataList[:m.rank-1:r.maxCount], r.dataList[m.rank:]...)
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delete(r.dataDict, k)
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return true
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}
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// upRank
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// @description: 排行升高
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// parameter:
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// @receiver r:
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// @curItem:当前对象
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// return:
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// @changeRank:排行是否变动
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// @dm:因排行变动被移除排行的对象
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func (r *RankUtil) upRank(curItem *Model) (changeRank bool, dm *Model) {
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changeRank = false
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for {
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// rank=1,排在第一位，下标为0，故这里需要-2为上一位的下标
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beforeIndex := curItem.rank - 2
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if beforeIndex < 0 {
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break
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}
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beforeItem := r.dataList[beforeIndex]
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if r.compar(curItem.obj, beforeItem.obj) <= 0 {
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break
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}
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// 交换操作
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tdm := r.exchange(curItem, beforeItem)
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if tdm != nil {
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dm = tdm
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}
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curItem = beforeItem
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changeRank = true
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}
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return
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}
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// downRank
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// @description: 排行降低
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// parameter:
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// @receiver r:
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// @curItem:当前对象
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// return:
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// @bool:
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func (r *RankUtil) downRank(curItem *Model) bool {
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changeRank := false
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for {
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// rank=1,排在第一位，下标为0，需要对比rank=2的，下标为1，故这里直接取rank即可
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afterIndex := curItem.rank
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if afterIndex >= len(r.dataList) {
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break
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}
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afterItem := r.dataList[afterIndex]
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if r.compar(afterItem.obj, curItem.obj) <= 0 {
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break
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}
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// 交换操作
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r.exchange(curItem, afterItem)
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curItem = afterItem
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changeRank = true
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}
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return changeRank
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}
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// exchange
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// @description: 排行对象交换
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// parameter:
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// @receiver r:
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// @a:对象a
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// @b:对象b
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// return:
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// @delRank:因交换被移除排行榜的对象
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func (r *RankUtil) exchange(a, b *Model) (dm *Model) {
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tempObj := a.obj
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tempKey := a.key
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a.obj = b.obj
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a.key = b.key
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b.obj = tempObj
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b.key = tempKey
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if a.rank > r.maxCount {
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delete(r.dataDict, a.key)
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dm = a
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} else {
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r.dataDict[a.key] = a
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}
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if b.rank > r.maxCount {
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delete(r.dataDict, b.key)
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dm = b
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} else {
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r.dataDict[b.key] = b
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}
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return
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}
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