117 lines
3.2 KiB
Go
117 lines
3.2 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
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// except in compliance with the License. You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed under the
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// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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package query
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import (
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"fmt"
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"github.com/blevesearch/bleve/analysis"
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"github.com/blevesearch/bleve/index"
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"github.com/blevesearch/bleve/mapping"
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"github.com/blevesearch/bleve/search"
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)
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type MatchPhraseQuery struct {
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MatchPhrase string `json:"match_phrase"`
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FieldVal string `json:"field,omitempty"`
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Analyzer string `json:"analyzer,omitempty"`
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BoostVal float64 `json:"boost,omitempty"`
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}
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// NewMatchPhraseQuery creates a new Query object
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// for matching phrases in the index.
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// An Analyzer is chosen based on the field.
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// Input text is analyzed using this analyzer.
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// Token terms resulting from this analysis are
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// used to build a search phrase. Result documents
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// must match this phrase. Queried field must have been indexed with
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// IncludeTermVectors set to true.
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func NewMatchPhraseQuery(matchPhrase string) *MatchPhraseQuery {
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return &MatchPhraseQuery{
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MatchPhrase: matchPhrase,
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BoostVal: 1.0,
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}
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}
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func (q *MatchPhraseQuery) Boost() float64 {
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return q.BoostVal
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}
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func (q *MatchPhraseQuery) SetBoost(b float64) Query {
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q.BoostVal = b
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return q
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}
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func (q *MatchPhraseQuery) Field() string {
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return q.FieldVal
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}
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func (q *MatchPhraseQuery) SetField(f string) Query {
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q.FieldVal = f
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return q
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}
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func (q *MatchPhraseQuery) Searcher(i index.IndexReader, m mapping.IndexMapping, explain bool) (search.Searcher, error) {
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field := q.FieldVal
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if q.FieldVal == "" {
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field = m.DefaultSearchField()
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}
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analyzerName := ""
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if q.Analyzer != "" {
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analyzerName = q.Analyzer
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} else {
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analyzerName = m.AnalyzerNameForPath(field)
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}
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analyzer := m.AnalyzerNamed(analyzerName)
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if analyzer == nil {
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return nil, fmt.Errorf("no analyzer named '%s' registered", q.Analyzer)
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}
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tokens := analyzer.Analyze([]byte(q.MatchPhrase))
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if len(tokens) > 0 {
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phrase := tokenStreamToPhrase(tokens)
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phraseQuery := NewPhraseQuery(phrase, field).SetBoost(q.BoostVal)
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return phraseQuery.Searcher(i, m, explain)
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}
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noneQuery := NewMatchNoneQuery()
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return noneQuery.Searcher(i, m, explain)
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}
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func tokenStreamToPhrase(tokens analysis.TokenStream) []string {
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firstPosition := int(^uint(0) >> 1)
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lastPosition := 0
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for _, token := range tokens {
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if token.Position < firstPosition {
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firstPosition = token.Position
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}
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if token.Position > lastPosition {
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lastPosition = token.Position
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}
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}
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phraseLen := lastPosition - firstPosition + 1
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if phraseLen > 0 {
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rv := make([]string, phraseLen)
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for i := 0; i < phraseLen; i++ {
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rv[i] = ""
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}
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for _, token := range tokens {
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pos := token.Position - firstPosition
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rv[pos] = string(token.Term)
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}
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return rv
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}
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return nil
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}
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func (q *MatchPhraseQuery) Validate() error {
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return nil
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}
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