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Analysis: Pattern Tokenizer, closes elastic#928.
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modules/elasticsearch/src/main/java/org/apache/lucene/analysis/pattern/PatternTokenizer.java
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| /* | ||
| * Licensed to Elastic Search and Shay Banon under one | ||
| * or more contributor license agreements. See the NOTICE file | ||
| * distributed with this work for additional information | ||
| * regarding copyright ownership. Elastic Search 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.apache.lucene.analysis.pattern; | ||
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| import org.apache.lucene.analysis.Tokenizer; | ||
| import org.apache.lucene.analysis.tokenattributes.CharTermAttribute; | ||
| import org.apache.lucene.analysis.tokenattributes.OffsetAttribute; | ||
|
|
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| import java.io.IOException; | ||
| import java.io.Reader; | ||
| import java.util.regex.Matcher; | ||
| import java.util.regex.Pattern; | ||
|
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| /** | ||
| * This tokenizer uses regex pattern matching to construct distinct tokens | ||
| * for the input stream. It takes two arguments: "pattern" and "group". | ||
| * <p/> | ||
| * <ul> | ||
| * <li>"pattern" is the regular expression.</li> | ||
| * <li>"group" says which group to extract into tokens.</li> | ||
| * </ul> | ||
| * <p> | ||
| * group=-1 (the default) is equivalent to "split". In this case, the tokens will | ||
| * be equivalent to the output from (without empty tokens): | ||
| * {@link String#split(java.lang.String)} | ||
| * </p> | ||
| * <p> | ||
| * Using group >= 0 selects the matching group as the token. For example, if you have:<br/> | ||
| * <pre> | ||
| * pattern = \'([^\']+)\' | ||
| * group = 0 | ||
| * input = aaa 'bbb' 'ccc' | ||
| * </pre> | ||
| * the output will be two tokens: 'bbb' and 'ccc' (including the ' marks). With the same input | ||
| * but using group=1, the output would be: bbb and ccc (no ' marks) | ||
| * </p> | ||
| * <p>NOTE: This Tokenizer does not output tokens that are of zero length.</p> | ||
| * | ||
| * @see Pattern | ||
| */ | ||
| public final class PatternTokenizer extends Tokenizer { | ||
|
|
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| private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class); | ||
| private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class); | ||
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| private final StringBuilder str = new StringBuilder(); | ||
| private int index; | ||
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| private final Pattern pattern; | ||
| private final int group; | ||
| private final Matcher matcher; | ||
|
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| /** | ||
| * creates a new PatternTokenizer returning tokens from group (-1 for split functionality) | ||
| */ | ||
| public PatternTokenizer(Reader input, Pattern pattern, int group) throws IOException { | ||
| super(input); | ||
| this.pattern = pattern; | ||
| this.group = group; | ||
| fillBuffer(str, input); | ||
| matcher = pattern.matcher(str); | ||
| index = 0; | ||
| } | ||
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| @Override | ||
| public boolean incrementToken() throws IOException { | ||
| if (index >= str.length()) return false; | ||
| clearAttributes(); | ||
| if (group >= 0) { | ||
|
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| // match a specific group | ||
| while (matcher.find()) { | ||
| index = matcher.start(group); | ||
| final int endIndex = matcher.end(group); | ||
| if (index == endIndex) continue; | ||
| termAtt.setEmpty().append(str, index, endIndex); | ||
| offsetAtt.setOffset(correctOffset(index), correctOffset(endIndex)); | ||
| return true; | ||
| } | ||
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| index = Integer.MAX_VALUE; // mark exhausted | ||
| return false; | ||
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| } else { | ||
|
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| // String.split() functionality | ||
| while (matcher.find()) { | ||
| if (matcher.start() - index > 0) { | ||
| // found a non-zero-length token | ||
| termAtt.setEmpty().append(str, index, matcher.start()); | ||
| offsetAtt.setOffset(correctOffset(index), correctOffset(matcher.start())); | ||
| index = matcher.end(); | ||
| return true; | ||
| } | ||
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| index = matcher.end(); | ||
| } | ||
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| if (str.length() - index == 0) { | ||
| index = Integer.MAX_VALUE; // mark exhausted | ||
| return false; | ||
| } | ||
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| termAtt.setEmpty().append(str, index, str.length()); | ||
| offsetAtt.setOffset(correctOffset(index), correctOffset(str.length())); | ||
| index = Integer.MAX_VALUE; // mark exhausted | ||
| return true; | ||
| } | ||
| } | ||
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| @Override | ||
| public void end() throws IOException { | ||
| final int ofs = correctOffset(str.length()); | ||
| offsetAtt.setOffset(ofs, ofs); | ||
| } | ||
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| @Override | ||
| public void reset(Reader input) throws IOException { | ||
| super.reset(input); | ||
| fillBuffer(str, input); | ||
| matcher.reset(str); | ||
| index = 0; | ||
| } | ||
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| // TODO: we should see if we can make this tokenizer work without reading | ||
| // the entire document into RAM, perhaps with Matcher.hitEnd/requireEnd ? | ||
| final char[] buffer = new char[8192]; | ||
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| private void fillBuffer(StringBuilder sb, Reader input) throws IOException { | ||
| int len; | ||
| sb.setLength(0); | ||
| while ((len = input.read(buffer)) > 0) { | ||
| sb.append(buffer, 0, len); | ||
| } | ||
| } | ||
| } |
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61
...elasticsearch/src/main/java/org/elasticsearch/index/analysis/PatternTokenizerFactory.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,61 @@ | ||
| /* | ||
| * Licensed to Elastic Search and Shay Banon under one | ||
| * or more contributor license agreements. See the NOTICE file | ||
| * distributed with this work for additional information | ||
| * regarding copyright ownership. Elastic Search 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. | ||
| */ | ||
|
|
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| package org.elasticsearch.index.analysis; | ||
|
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| import org.apache.lucene.analysis.Tokenizer; | ||
| import org.apache.lucene.analysis.pattern.PatternTokenizer; | ||
| import org.elasticsearch.ElasticSearchIllegalArgumentException; | ||
| import org.elasticsearch.ElasticSearchIllegalStateException; | ||
| import org.elasticsearch.common.inject.Inject; | ||
| import org.elasticsearch.common.inject.assistedinject.Assisted; | ||
| import org.elasticsearch.common.regex.Regex; | ||
| import org.elasticsearch.common.settings.Settings; | ||
| import org.elasticsearch.index.Index; | ||
| import org.elasticsearch.index.settings.IndexSettings; | ||
|
|
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| import java.io.IOException; | ||
| import java.io.Reader; | ||
| import java.util.regex.Pattern; | ||
|
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| public class PatternTokenizerFactory extends AbstractTokenizerFactory { | ||
|
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| private final Pattern pattern; | ||
| private final int group; | ||
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| @Inject public PatternTokenizerFactory(Index index, @IndexSettings Settings indexSettings, @Assisted String name, @Assisted Settings settings) { | ||
| super(index, indexSettings, name, settings); | ||
|
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| String sPattern = settings.get("pattern", "\\W+" /*PatternAnalyzer.NON_WORD_PATTERN*/); | ||
| if (sPattern == null) { | ||
| throw new ElasticSearchIllegalArgumentException("pattern is missing for [" + name + "] tokenizer of type 'pattern'"); | ||
| } | ||
|
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| this.pattern = Regex.compile(sPattern, settings.get("flags")); | ||
| this.group = settings.getAsInt("group", -1); | ||
| } | ||
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| @Override public Tokenizer create(Reader reader) { | ||
| try { | ||
| return new PatternTokenizer(reader, pattern, group); | ||
| } catch (IOException e) { | ||
| throw new ElasticSearchIllegalStateException("failed to create pattern tokenizer", e); | ||
| } | ||
| } | ||
| } |
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