72 lines
2.1 KiB
Go
72 lines
2.1 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 elision_filter
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import (
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"bytes"
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"fmt"
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"github.com/blevesearch/bleve/analysis"
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"github.com/blevesearch/bleve/registry"
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)
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const Name = "elision"
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const RightSingleQoutationMark = "’"
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const Apostrophe = "'"
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const Apostrophes = Apostrophe + RightSingleQoutationMark
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type ElisionFilter struct {
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articles analysis.TokenMap
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}
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func NewElisionFilter(articles analysis.TokenMap) *ElisionFilter {
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return &ElisionFilter{
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articles: articles,
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}
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}
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func (s *ElisionFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
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rv := make(analysis.TokenStream, 0)
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for _, token := range input {
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firstApostrophe := bytes.IndexAny(token.Term, Apostrophes)
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if firstApostrophe >= 0 {
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// found an apostrophe
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prefix := token.Term[0:firstApostrophe]
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// see if the prefix matches one of the articles
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_, articleMatch := s.articles[string(prefix)]
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if articleMatch {
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token.Term = token.Term[firstApostrophe+1:]
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}
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}
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rv = append(rv, token)
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}
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return rv
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}
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func ElisionFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
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articlesTokenMapName, ok := config["articles_token_map"].(string)
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if !ok {
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return nil, fmt.Errorf("must specify articles_token_map")
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}
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articlesTokenMap, err := cache.TokenMapNamed(articlesTokenMapName)
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if err != nil {
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return nil, fmt.Errorf("error building elision filter: %v", err)
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}
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return NewElisionFilter(articlesTokenMap), nil
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}
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func init() {
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registry.RegisterTokenFilter(Name, ElisionFilterConstructor)
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}
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