/*
* 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 org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
import org.apache.lucene.util.AttributeFactory;
/** A grammar-based tokenizer constructed with JFlex
*
* <p> This should be a good tokenizer for most European-language documents:
*
* <ul>
* <li>Splits words at punctuation characters, removing punctuation. However, a
* dot that's not followed by whitespace is considered part of a token.
* <li>Splits words at hyphens, unless there's a number in the token, in which case
* the whole token is interpreted as a product number and is not split.
* <li>Recognizes email addresses and internet hostnames as one token.
* </ul>
*
* <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.
*
* ClassicTokenizer was named StandardTokenizer in Lucene versions prior to 3.1.
* As of 3.1, {@link StandardTokenizer} implements Unicode text segmentation,
* as specified by UAX#29.
*/
public final class ClassicTokenizer extends Tokenizer {
/** A private instance of the JFlex-constructed scanner */
private ClassicTokenizerImpl scanner;
public static final int ALPHANUM = 0;
public static final int APOSTROPHE = 1;
public static final int ACRONYM = 2;
public static final int COMPANY = 3;
public static final int EMAIL = 4;
public static final int HOST = 5;
public static final int NUM = 6;
public static final int CJ = 7;
public static final int ACRONYM_DEP = 8;
/** 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>"
};
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 ClassicTokenizer}. Attaches
* the <code>input</code> to the newly created JFlex scanner.
*
* See http://issues.apache.org/jira/browse/LUCENE-1068
*/
public ClassicTokenizer() {
init();
}
/**
* Creates a new ClassicTokenizer with a given {@link org.apache.lucene.util.AttributeFactory}
*/
public ClassicTokenizer(AttributeFactory factory) {
super(factory);
init();
}
private void init() {
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 == ClassicTokenizerImpl.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()));
if (tokenType == ClassicTokenizer.ACRONYM_DEP) {
typeAtt.setType(ClassicTokenizer.TOKEN_TYPES[ClassicTokenizer.HOST]);
termAtt.setLength(termAtt.length() - 1); // remove extra '.'
} else {
typeAtt.setType(ClassicTokenizer.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;
}
}