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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 query
import (
"fmt"
"github.com/blevesearch/bleve/analysis"
"github.com/blevesearch/bleve/index"
"github.com/blevesearch/bleve/mapping"
"github.com/blevesearch/bleve/search"
)
type MatchPhraseQuery struct {
MatchPhrase string `json:"match_phrase"`
FieldVal string `json:"field,omitempty"`
Analyzer string `json:"analyzer,omitempty"`
BoostVal *Boost `json:"boost,omitempty"`
}
// NewMatchPhraseQuery creates a new Query object
// for matching phrases in the index.
// An Analyzer is chosen based on the field.
// Input text is analyzed using this analyzer.
// Token terms resulting from this analysis are
// used to build a search phrase. Result documents
// must match this phrase. Queried field must have been indexed with
// IncludeTermVectors set to true.
func NewMatchPhraseQuery(matchPhrase string) *MatchPhraseQuery {
return &MatchPhraseQuery{
MatchPhrase: matchPhrase,
}
}
func (q *MatchPhraseQuery) SetBoost(b float64) {
boost := Boost(b)
q.BoostVal = &boost
}
func (q *MatchPhraseQuery) Boost() float64{
return q.BoostVal.Value()
}
func (q *MatchPhraseQuery) SetField(f string) {
q.FieldVal = f
}
func (q *MatchPhraseQuery) Field() string{
return q.FieldVal
}
func (q *MatchPhraseQuery) Searcher(i index.IndexReader, m mapping.IndexMapping, explain bool) (search.Searcher, error) {
field := q.FieldVal
if q.FieldVal == "" {
field = m.DefaultSearchField()
}
analyzerName := ""
if q.Analyzer != "" {
analyzerName = q.Analyzer
} else {
analyzerName = m.AnalyzerNameForPath(field)
}
analyzer := m.AnalyzerNamed(analyzerName)
if analyzer == nil {
return nil, fmt.Errorf("no analyzer named '%s' registered", q.Analyzer)
}
tokens := analyzer.Analyze([]byte(q.MatchPhrase))
if len(tokens) > 0 {
phrase := tokenStreamToPhrase(tokens)
phraseQuery := NewPhraseQuery(phrase, field)
phraseQuery.SetBoost(q.BoostVal.Value())
return phraseQuery.Searcher(i, m, explain)
}
noneQuery := NewMatchNoneQuery()
return noneQuery.Searcher(i, m, explain)
}
func tokenStreamToPhrase(tokens analysis.TokenStream) []string {
firstPosition := int(^uint(0) >> 1)
lastPosition := 0
for _, token := range tokens {
if token.Position < firstPosition {
firstPosition = token.Position
}
if token.Position > lastPosition {
lastPosition = token.Position
}
}
phraseLen := lastPosition - firstPosition + 1
if phraseLen > 0 {
rv := make([]string, phraseLen)
for i := 0; i < phraseLen; i++ {
rv[i] = ""
}
for _, token := range tokens {
pos := token.Position - firstPosition
rv[pos] = string(token.Term)
}
return rv
}
return nil
}