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- // Copyright (c) 2014 Couchbase, Inc.
- //
- // Licensed under the Apache License, Version 2.0 (the "License");
- // you may not use this file except in compliance with the License.
- // You may obtain a copy of the License at
- //
- // http://www.apache.org/licenses/LICENSE-2.0
- //
- // Unless required by applicable law or agreed to in writing, software
- // distributed under the License is distributed on an "AS IS" BASIS,
- // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- // See the License for the specific language governing permissions and
- // limitations under the License.
-
- package scorer
-
- import (
- "fmt"
-
- "github.com/blevesearch/bleve/index"
- "github.com/blevesearch/bleve/search"
- )
-
- type ConstantScorer struct {
- constant float64
- boost float64
- options search.SearcherOptions
- queryNorm float64
- queryWeight float64
- queryWeightExplanation *search.Explanation
- }
-
- func NewConstantScorer(constant float64, boost float64, options search.SearcherOptions) *ConstantScorer {
- rv := ConstantScorer{
- options: options,
- queryWeight: 1.0,
- constant: constant,
- boost: boost,
- }
-
- return &rv
- }
-
- func (s *ConstantScorer) Weight() float64 {
- sum := s.boost
- return sum * sum
- }
-
- func (s *ConstantScorer) SetQueryNorm(qnorm float64) {
- s.queryNorm = qnorm
-
- // update the query weight
- s.queryWeight = s.boost * s.queryNorm
-
- if s.options.Explain {
- childrenExplanations := make([]*search.Explanation, 2)
- childrenExplanations[0] = &search.Explanation{
- Value: s.boost,
- Message: "boost",
- }
- childrenExplanations[1] = &search.Explanation{
- Value: s.queryNorm,
- Message: "queryNorm",
- }
- s.queryWeightExplanation = &search.Explanation{
- Value: s.queryWeight,
- Message: fmt.Sprintf("ConstantScore()^%f, product of:", s.boost),
- Children: childrenExplanations,
- }
- }
- }
-
- func (s *ConstantScorer) Score(ctx *search.SearchContext, id index.IndexInternalID) *search.DocumentMatch {
- var scoreExplanation *search.Explanation
-
- score := s.constant
-
- if s.options.Explain {
- scoreExplanation = &search.Explanation{
- Value: score,
- Message: fmt.Sprintf("ConstantScore()"),
- }
- }
-
- // if the query weight isn't 1, multiply
- if s.queryWeight != 1.0 {
- score = score * s.queryWeight
- if s.options.Explain {
- childExplanations := make([]*search.Explanation, 2)
- childExplanations[0] = s.queryWeightExplanation
- childExplanations[1] = scoreExplanation
- scoreExplanation = &search.Explanation{
- Value: score,
- Message: fmt.Sprintf("weight(^%f), product of:", s.boost),
- Children: childExplanations,
- }
- }
- }
-
- rv := ctx.DocumentMatchPool.Get()
- rv.IndexInternalID = id
- rv.Score = score
- if s.options.Explain {
- rv.Expl = scoreExplanation
- }
-
- return rv
- }
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