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71 lines
1.9 KiB
71 lines
1.9 KiB
// Copyright (c) 2014 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package stop implements a TokenFilter removing tokens found in
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// a TokenMap.
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//
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// It constructor takes the following arguments:
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//
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// "stop_token_map" (string): the name of the token map identifying tokens to
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// remove.
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package stop
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import (
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"fmt"
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"github.com/blevesearch/bleve/v2/analysis"
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"github.com/blevesearch/bleve/v2/registry"
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)
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const Name = "stop_tokens"
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type StopTokensFilter struct {
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stopTokens analysis.TokenMap
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}
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func NewStopTokensFilter(stopTokens analysis.TokenMap) *StopTokensFilter {
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return &StopTokensFilter{
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stopTokens: stopTokens,
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}
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}
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func (f *StopTokensFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
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j := 0
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for _, token := range input {
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_, isStopToken := f.stopTokens[string(token.Term)]
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if !isStopToken {
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input[j] = token
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j++
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}
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}
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return input[:j]
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}
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func StopTokensFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
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stopTokenMapName, ok := config["stop_token_map"].(string)
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if !ok {
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return nil, fmt.Errorf("must specify stop_token_map")
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}
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stopTokenMap, err := cache.TokenMapNamed(stopTokenMapName)
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if err != nil {
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return nil, fmt.Errorf("error building stop words filter: %v", err)
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}
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return NewStopTokensFilter(stopTokenMap), nil
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}
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func init() {
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registry.RegisterTokenFilter(Name, StopTokensFilterConstructor)
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}
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