Ejemplo n.º 1
0
// 给文档评分并排序
func (ranker *Ranker) Rank(
	docs []types.IndexedDocument, options types.RankOptions, countDocsOnly bool) (types.ScoredDocuments, int) {
	if ranker.initialized == false {
		log.Fatal("排序器尚未初始化")
	}

	// 对每个文档评分
	var outputDocs types.ScoredDocuments
	numDocs := 0
	for _, d := range docs {
		ranker.lock.RLock()
		// 判断doc是否存在
		if _, ok := ranker.lock.docs[d.DocId]; ok {
			fs := ranker.lock.fields[d.DocId]
			ranker.lock.RUnlock()
			// 计算评分并剔除没有分值的文档
			scores := options.ScoringCriteria.Score(d, fs)
			if len(scores) > 0 {
				if !countDocsOnly {
					outputDocs = append(outputDocs, types.ScoredDocument{
						DocId:                 d.DocId,
						Scores:                scores,
						TokenSnippetLocations: d.TokenSnippetLocations,
						TokenLocations:        d.TokenLocations})
				}
				numDocs++
			}
		} else {
			ranker.lock.RUnlock()
		}
	}

	// 排序
	if !countDocsOnly {
		if options.ReverseOrder {
			sort.Sort(sort.Reverse(outputDocs))
		} else {
			sort.Sort(outputDocs)
		}
		// 当用户要求只返回部分结果时返回部分结果
		var start, end int
		if options.MaxOutputs != 0 {
			start = utils.MinInt(options.OutputOffset, len(outputDocs))
			end = utils.MinInt(options.OutputOffset+options.MaxOutputs, len(outputDocs))
		} else {
			start = utils.MinInt(options.OutputOffset, len(outputDocs))
			end = len(outputDocs)
		}
		return outputDocs[start:end], numDocs
	}
	return outputDocs, numDocs
}
Ejemplo n.º 2
0
func (docs ScoredDocuments) Less(i, j int) bool {
	// 为了从大到小排序,这实际上实现的是More的功能
	for iScore := 0; iScore < utils.MinInt(len(docs[i].Scores), len(docs[j].Scores)); iScore++ {
		if docs[i].Scores[iScore] > docs[j].Scores[iScore] {
			return true
		} else if docs[i].Scores[iScore] < docs[j].Scores[iScore] {
			return false
		}
	}
	return len(docs[i].Scores) > len(docs[j].Scores)
}
Ejemplo n.º 3
0
// 查找满足搜索条件的文档,此函数线程安全
func (engine *Engine) Search(request types.SearchRequest) (output types.SearchResponse) {
	if !engine.initialized {
		log.Fatal("必须先初始化引擎")
	}

	var rankOptions types.RankOptions
	if request.RankOptions == nil {
		rankOptions = *engine.initOptions.DefaultRankOptions
	} else {
		rankOptions = *request.RankOptions
	}
	if rankOptions.ScoringCriteria == nil {
		rankOptions.ScoringCriteria = engine.initOptions.DefaultRankOptions.ScoringCriteria
	}

	// 收集关键词
	tokens := []string{}
	if request.Text != "" {
		querySegments := engine.segmenter.Segment([]byte(request.Text))
		for _, s := range querySegments {
			token := s.Token().Text()
			if !engine.stopTokens.IsStopToken(token) {
				tokens = append(tokens, s.Token().Text())
			}
		}
	} else {
		for _, t := range request.Tokens {
			tokens = append(tokens, t)
		}
	}

	// 建立排序器返回的通信通道
	rankerReturnChannel := make(
		chan rankerReturnRequest, engine.initOptions.NumShards)

	// 生成查找请求
	lookupRequest := indexerLookupRequest{
		countDocsOnly:       request.CountDocsOnly,
		tokens:              tokens,
		labels:              request.Labels,
		docIds:              request.DocIds,
		options:             rankOptions,
		rankerReturnChannel: rankerReturnChannel,
	}

	// 向索引器发送查找请求
	for shard := 0; shard < engine.initOptions.NumShards; shard++ {
		engine.indexerLookupChannels[shard] <- lookupRequest
	}

	// 从通信通道读取排序器的输出
	numDocs := 0
	rankOutput := types.ScoredDocuments{}
	timeout := request.Timeout
	isTimeout := false
	if timeout <= 0 {
		// 不设置超时
		for shard := 0; shard < engine.initOptions.NumShards; shard++ {
			rankerOutput := <-rankerReturnChannel
			if !request.CountDocsOnly {
				for _, doc := range rankerOutput.docs {
					rankOutput = append(rankOutput, doc)
				}
			}
			numDocs += rankerOutput.numDocs
		}
	} else {
		// 设置超时
		deadline := time.Now().Add(time.Nanosecond * time.Duration(NumNanosecondsInAMillisecond*request.Timeout))
		for shard := 0; shard < engine.initOptions.NumShards; shard++ {
			select {
			case rankerOutput := <-rankerReturnChannel:
				if !request.CountDocsOnly {
					for _, doc := range rankerOutput.docs {
						rankOutput = append(rankOutput, doc)
					}
				}
				numDocs += rankerOutput.numDocs
			case <-time.After(deadline.Sub(time.Now())):
				isTimeout = true
				break
			}
		}
	}

	// 再排序
	if !request.CountDocsOnly {
		if rankOptions.ReverseOrder {
			sort.Sort(sort.Reverse(rankOutput))
		} else {
			sort.Sort(rankOutput)
		}
	}

	// 准备输出
	output.Tokens = tokens
	if !request.CountDocsOnly {
		var start, end int
		if rankOptions.MaxOutputs == 0 {
			start = utils.MinInt(rankOptions.OutputOffset, len(rankOutput))
			end = len(rankOutput)
		} else {
			start = utils.MinInt(rankOptions.OutputOffset, len(rankOutput))
			end = utils.MinInt(start+rankOptions.MaxOutputs, len(rankOutput))
		}
		output.Docs = rankOutput[start:end]
	}
	output.NumDocs = numDocs
	output.Timeout = isTimeout
	return
}