/**
* 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 com.antbrains.wordseg.luceneanalyzer;
import java.io.IOException;
import java.io.Reader;
/**
* A grammar-based tokenizer constructed with JFlex.
* <p>
* As of Lucene version 3.1, this class implements the Word Break rules from the Unicode Text
* Segmentation algorithm, as specified in <a href="http://unicode.org/reports/tr29/">Unicode
* Standard Annex #29</a>.
* <p/>
* <p>
* 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.
*
* <a name="version"/>
* <p>
* You must specify the required {@link Version} compatibility when creating StandardTokenizer:
* <ul>
* <li>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.
* </ul>
*/
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[] { "<ALPHANUM>", "<APOSTROPHE>",
"<ACRONYM>", "<COMPANY>", "<EMAIL>", "<HOST>", "<NUM>", "<CJ>", "<ACRONYM_DEP>",
"<SOUTHEAST_ASIAN>", "<IDEOGRAPHIC>", "<HIRAGANA>", "<KATAKANA>", "<HANGUL>" };
public static final int DEFAULT_MAX_TOKEN_LENGTH = 255;
private int maxTokenLength = DEFAULT_MAX_TOKEN_LENGTH;
/**
* Set the max allowed token length. Any token longer than this is skipped.
*/
public void setMaxTokenLength(int length) {
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 <code>input</code> 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();
init(input, matchVersion);
}
/**
* Creates a new StandardTokenizer with a given {@link AttributeSource}.
*/
public StandardTokenizer(Version matchVersion, AttributeSource source, Reader input) {
super(source);
init(input, matchVersion);
}
/**
* Creates a new StandardTokenizer with a given
* {@link org.apache.lucene.util.AttributeSource.AttributeFactory}
*/
public StandardTokenizer(Version matchVersion, AttributeFactory factory, Reader input) {
super(factory);
init(input, matchVersion);
}
private final void init(Reader input, Version matchVersion) {
this.scanner = matchVersion.onOrAfter(Version.LUCENE_29) ? new StandardTokenizerImpl(input)
: new ClassicTokenizerImpl(input);
this.input = 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();
int posIncr = 1;
while (true) {
int tokenType = scanner.getNextToken();
if (tokenType == StandardTokenizerInterface.YYEOF) {
return false;
}
if (scanner.yylength() <= maxTokenLength) {
posIncrAtt.setPositionIncrement(posIncr);
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
posIncr++;
}
}
@Override
public final void end() {
// set final offset
int finalOffset = correctOffset(scanner.yychar() + scanner.yylength());
offsetAtt.setOffset(finalOffset, finalOffset);
}
@Override
public void reset(Reader reader) throws IOException {
super.reset(reader);
scanner.yyreset(reader);
}
}