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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 analysis
-
- import (
- "fmt"
- "time"
- )
-
- type CharFilter interface {
- Filter([]byte) []byte
- }
-
- type TokenType int
-
- const (
- AlphaNumeric TokenType = iota
- Ideographic
- Numeric
- DateTime
- Shingle
- Single
- Double
- Boolean
- )
-
- // Token represents one occurrence of a term at a particular location in a
- // field.
- type Token struct {
- // Start specifies the byte offset of the beginning of the term in the
- // field.
- Start int `json:"start"`
-
- // End specifies the byte offset of the end of the term in the field.
- End int `json:"end"`
- Term []byte `json:"term"`
-
- // Position specifies the 1-based index of the token in the sequence of
- // occurrences of its term in the field.
- Position int `json:"position"`
- Type TokenType `json:"type"`
- KeyWord bool `json:"keyword"`
- }
-
- func (t *Token) String() string {
- return fmt.Sprintf("Start: %d End: %d Position: %d Token: %s Type: %d", t.Start, t.End, t.Position, string(t.Term), t.Type)
- }
-
- type TokenStream []*Token
-
- // A Tokenizer splits an input string into tokens, the usual behaviour being to
- // map words to tokens.
- type Tokenizer interface {
- Tokenize([]byte) TokenStream
- }
-
- // A TokenFilter adds, transforms or removes tokens from a token stream.
- type TokenFilter interface {
- Filter(TokenStream) TokenStream
- }
-
- type Analyzer struct {
- CharFilters []CharFilter
- Tokenizer Tokenizer
- TokenFilters []TokenFilter
- }
-
- func (a *Analyzer) Analyze(input []byte) TokenStream {
- if a.CharFilters != nil {
- for _, cf := range a.CharFilters {
- input = cf.Filter(input)
- }
- }
- tokens := a.Tokenizer.Tokenize(input)
- if a.TokenFilters != nil {
- for _, tf := range a.TokenFilters {
- tokens = tf.Filter(tokens)
- }
- }
- return tokens
- }
-
- var ErrInvalidDateTime = fmt.Errorf("unable to parse datetime with any of the layouts")
-
- type DateTimeParser interface {
- ParseDateTime(string) (time.Time, error)
- }
-
- type ByteArrayConverter interface {
- Convert([]byte) (interface{}, error)
- }
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