org.apache.tika.eval.tokens.CJKBigramAwareLengthFilterFactory Maven / Gradle / Ivy
/*
* 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.tika.eval.tokens;
import java.io.IOException;
import java.util.Map;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.cjk.CJKBigramFilter;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
import org.apache.lucene.analysis.FilteringTokenFilter;
import org.apache.lucene.analysis.util.TokenFilterFactory;
/**
* Creates a very narrowly focused TokenFilter that limits tokens based on length
* _unless_ they've been identified as <DOUBLE> or <SINGLE>
* by the CJKBigramFilter.
*
* This class is intended to be used when generating "common tokens" files.
*/
public class CJKBigramAwareLengthFilterFactory extends TokenFilterFactory {
private final int min;
private final int max;
public CJKBigramAwareLengthFilterFactory(Map args) {
super(args);
min = Integer.parseInt(args.get("min"));
max = Integer.parseInt(args.get("max"));
}
@Override
public TokenStream create(TokenStream tokenStream) {
return new CJKAwareLengthFilter(tokenStream);
}
private class CJKAwareLengthFilter extends FilteringTokenFilter {
private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
private final TypeAttribute typeAtt = addAttribute(TypeAttribute.class);
public CJKAwareLengthFilter(TokenStream in) {
super(in);
}
@Override
protected boolean accept() throws IOException {
if ( termAtt.length() < min) {
String type = typeAtt.type();
if (type == CJKBigramFilter.DOUBLE_TYPE || type == CJKBigramFilter.SINGLE_TYPE) {
return true;
}
}
return termAtt.length() >= min && termAtt.length() <= max;
}
}
/*
private static boolean isCJ(int codePoint) {
if (
(codePoint >= 0x4E00 && codePoint <= 0x9FFF) ||
( codePoint >= 0x3400 && codePoint <= 0x4dbf) ||
( codePoint >= 0x20000 && codePoint <= 0x2a6df) ||
( codePoint >= 0x2A700 && codePoint <= 0x2b73f) ||
( codePoint >= 0x2B740 && codePoint <= 0x2B81F) ||
( codePoint >= 0x2B820 && codePoint <- 0x2CEAF) ||
( codePoint >= 0xF900 && codePoint <= 0xFAFF) ||
( codePoint >= 0x2F800 && codePoint <= 0x2Fa1F)
) {
return true;
}
return false;
}*/
}