org.apache.lucene.analysis.standard.StandardTokenizer Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.standard;
import java.io.IOException;
import java.io.Reader;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.standard.std31.StandardTokenizerImpl31;
import org.apache.lucene.analysis.standard.std34.StandardTokenizerImpl34;
import org.apache.lucene.analysis.standard.std40.StandardTokenizerImpl40;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
import org.apache.lucene.util.AttributeFactory;
import org.apache.lucene.util.AttributeSource;
import org.apache.lucene.util.Version;
/** A grammar-based tokenizer constructed with JFlex.
*
* As of Lucene version 3.1, this class implements the Word Break rules from the
* Unicode Text Segmentation algorithm, as specified in
* Unicode Standard Annex #29.
*
* Many applications have specific tokenizer needs. If this tokenizer does
* not suit your application, please consider copying this source code
* directory to your project and maintaining your own grammar-based tokenizer.
*
*
*
You must specify the required {@link Version}
* compatibility when creating StandardTokenizer:
*
* - As of 3.4, Hiragana and Han characters are no longer wrongly split
* from their combining characters. If you use a previous version number,
* you get the exact broken behavior for backwards compatibility.
*
- As of 3.1, StandardTokenizer implements Unicode text segmentation.
* If you use a previous version number, you get the exact behavior of
* {@link ClassicTokenizer} for backwards compatibility.
*
*/
public final class StandardTokenizer extends Tokenizer {
/** A private instance of the JFlex-constructed scanner */
private StandardTokenizerInterface scanner;
public static final int ALPHANUM = 0;
/** @deprecated (3.1) */
@Deprecated
public static final int APOSTROPHE = 1;
/** @deprecated (3.1) */
@Deprecated
public static final int ACRONYM = 2;
/** @deprecated (3.1) */
@Deprecated
public static final int COMPANY = 3;
public static final int EMAIL = 4;
/** @deprecated (3.1) */
@Deprecated
public static final int HOST = 5;
public static final int NUM = 6;
/** @deprecated (3.1) */
@Deprecated
public static final int CJ = 7;
/** @deprecated (3.1) */
@Deprecated
public static final int ACRONYM_DEP = 8;
public static final int SOUTHEAST_ASIAN = 9;
public static final int IDEOGRAPHIC = 10;
public static final int HIRAGANA = 11;
public static final int KATAKANA = 12;
public static final int HANGUL = 13;
/** String token types that correspond to token type int constants */
public static final String [] TOKEN_TYPES = new String [] {
"",
"",
"",
"",
"",
"",
"",
"",
"",
"",
"",
"",
"",
""
};
private int skippedPositions;
private int maxTokenLength = StandardAnalyzer.DEFAULT_MAX_TOKEN_LENGTH;
/** Set the max allowed token length. Any token longer
* than this is skipped. */
public void setMaxTokenLength(int length) {
if (length < 1) {
throw new IllegalArgumentException("maxTokenLength must be greater than zero");
}
this.maxTokenLength = length;
}
/** @see #setMaxTokenLength */
public int getMaxTokenLength() {
return maxTokenLength;
}
/**
* Creates a new instance of the {@link org.apache.lucene.analysis.standard.StandardTokenizer}. Attaches
* the input to the newly created JFlex scanner.
*
* @param input The input reader
*
* See http://issues.apache.org/jira/browse/LUCENE-1068
*/
public StandardTokenizer(Version matchVersion, Reader input) {
super(input);
init(matchVersion);
}
/**
* Creates a new StandardTokenizer with a given {@link org.apache.lucene.util.AttributeFactory}
*/
public StandardTokenizer(Version matchVersion, AttributeFactory factory, Reader input) {
super(factory, input);
init(matchVersion);
}
private final void init(Version matchVersion) {
if (matchVersion.onOrAfter(Version.LUCENE_4_7)) {
this.scanner = new StandardTokenizerImpl(input);
} else if (matchVersion.onOrAfter(Version.LUCENE_4_0)) {
this.scanner = new StandardTokenizerImpl40(input);
} else if (matchVersion.onOrAfter(Version.LUCENE_3_4)) {
this.scanner = new StandardTokenizerImpl34(input);
} else if (matchVersion.onOrAfter(Version.LUCENE_3_1)) {
this.scanner = new StandardTokenizerImpl31(input);
} else {
this.scanner = new ClassicTokenizerImpl(input);
}
}
// this tokenizer generates three attributes:
// term offset, positionIncrement and type
private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
private final TypeAttribute typeAtt = addAttribute(TypeAttribute.class);
/*
* (non-Javadoc)
*
* @see org.apache.lucene.analysis.TokenStream#next()
*/
@Override
public final boolean incrementToken() throws IOException {
clearAttributes();
skippedPositions = 0;
while(true) {
int tokenType = scanner.getNextToken();
if (tokenType == StandardTokenizerInterface.YYEOF) {
return false;
}
if (scanner.yylength() <= maxTokenLength) {
posIncrAtt.setPositionIncrement(skippedPositions+1);
scanner.getText(termAtt);
final int start = scanner.yychar();
offsetAtt.setOffset(correctOffset(start), correctOffset(start+termAtt.length()));
// This 'if' should be removed in the next release. For now, it converts
// invalid acronyms to HOST. When removed, only the 'else' part should
// remain.
if (tokenType == StandardTokenizer.ACRONYM_DEP) {
typeAtt.setType(StandardTokenizer.TOKEN_TYPES[StandardTokenizer.HOST]);
termAtt.setLength(termAtt.length() - 1); // remove extra '.'
} else {
typeAtt.setType(StandardTokenizer.TOKEN_TYPES[tokenType]);
}
return true;
} else
// When we skip a too-long term, we still increment the
// position increment
skippedPositions++;
}
}
@Override
public final void end() throws IOException {
super.end();
// set final offset
int finalOffset = correctOffset(scanner.yychar() + scanner.yylength());
offsetAtt.setOffset(finalOffset, finalOffset);
// adjust any skipped tokens
posIncrAtt.setPositionIncrement(posIncrAtt.getPositionIncrement()+skippedPositions);
}
@Override
public void close() throws IOException {
super.close();
scanner.yyreset(input);
}
@Override
public void reset() throws IOException {
super.reset();
scanner.yyreset(input);
skippedPositions = 0;
}
}