1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.index.analysis;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.miscellaneous.KeepWordFilter;
import org.apache.lucene.analysis.miscellaneous.Lucene43KeepWordFilter;
import org.apache.lucene.analysis.util.CharArraySet;
import org.apache.lucene.util.Version;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.env.Environment;
import org.elasticsearch.index.IndexSettings;
/**
* A {@link TokenFilterFactory} for {@link KeepWordFilter}. This filter only
* keep tokens that are contained in the term set configured via
* {@value #KEEP_WORDS_KEY} setting. This filter acts like an inverse stop
* filter.
* <p>
* Configuration options:
* <ul>
* <li>{@value #KEEP_WORDS_KEY} the array of words / tokens to keep.</li>
* <li>{@value #KEEP_WORDS_PATH_KEY} an reference to a file containing the words
* / tokens to keep. Note: this is an alternative to {@value #KEEP_WORDS_KEY} if
* both are set an exception will be thrown.</li>
* <li>{@value #ENABLE_POS_INC_KEY} <code>true</code> iff the filter should
* maintain position increments for dropped tokens. The default is
* <code>true</code>.</li>
* <li>{@value #KEEP_WORDS_CASE_KEY} to use case sensitive keep words. The
* default is <code>false</code> which corresponds to case-sensitive.</li>
* </ul>
*
* @see StopTokenFilterFactory
*/
public class KeepWordFilterFactory extends AbstractTokenFilterFactory {
private final CharArraySet keepWords;
private final boolean enablePositionIncrements;
private static final String KEEP_WORDS_KEY = "keep_words";
private static final String KEEP_WORDS_PATH_KEY = KEEP_WORDS_KEY + "_path";
private static final String KEEP_WORDS_CASE_KEY = KEEP_WORDS_KEY + "_case"; // for javadoc
private static final String ENABLE_POS_INC_KEY = "enable_position_increments";
public KeepWordFilterFactory(IndexSettings indexSettings,
Environment env, String name, Settings settings) {
super(indexSettings, name, settings);
final String[] arrayKeepWords = settings.getAsArray(KEEP_WORDS_KEY, null);
final String keepWordsPath = settings.get(KEEP_WORDS_PATH_KEY, null);
if ((arrayKeepWords == null && keepWordsPath == null) || (arrayKeepWords != null && keepWordsPath != null)) {
// we don't allow both or none
throw new IllegalArgumentException("keep requires either `" + KEEP_WORDS_KEY + "` or `"
+ KEEP_WORDS_PATH_KEY + "` to be configured");
}
if (version.onOrAfter(Version.LUCENE_4_4) && settings.get(ENABLE_POS_INC_KEY) != null) {
throw new IllegalArgumentException(ENABLE_POS_INC_KEY + " is not supported anymore. Please fix your analysis chain or use"
+ " an older compatibility version (<=4.3) but beware that it might cause highlighting bugs.");
}
enablePositionIncrements = version.onOrAfter(Version.LUCENE_4_4) ? true : settings.getAsBoolean(ENABLE_POS_INC_KEY, true);
this.keepWords = Analysis.getWordSet(env, settings, KEEP_WORDS_KEY);
}
@Override
public TokenStream create(TokenStream tokenStream) {
if (version.onOrAfter(Version.LUCENE_4_4)) {
return new KeepWordFilter(tokenStream, keepWords);
} else {
@SuppressWarnings("deprecation")
final TokenStream filter = new Lucene43KeepWordFilter(enablePositionIncrements, tokenStream, keepWords);
return filter;
}
}
}
|
