nl.inl.blacklab.filter.DesensitizeFilter.java Source code

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Here is the source code for nl.inl.blacklab.filter.DesensitizeFilter.java

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/*******************************************************************************
 * Copyright (c) 2010, 2012 Institute for Dutch Lexicology
 *
 * Licensed 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 nl.inl.blacklab.filter;

import java.io.IOException;

import org.apache.commons.lang3.StringUtils;
import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;

/**
 * Lowercases and/or removes any accents from the input.
 *
 * NOTE: Lucene includes ASCIIFoldingFilter, but this works with non-ASCII characters too.
 *
 * Uses Normalizer, so Java 1.6+ is needed. If this is not available, use an approach such as
 * RemoveDutchAccentsFilter.
 */
public class DesensitizeFilter extends TokenFilter {

    private CharTermAttribute termAtt;

    private boolean lowerCase;

    private boolean removeAccents;

    /**
     * @param input the token stream to desensitize
     * @param lowerCase whether to lower case tokens
     * @param removeAccents whether to remove accents
     */
    public DesensitizeFilter(TokenStream input, boolean lowerCase, boolean removeAccents) {
        super(input);
        this.lowerCase = lowerCase;
        this.removeAccents = removeAccents;
        termAtt = addAttribute(CharTermAttribute.class);
    }

    @Override
    final public boolean incrementToken() throws IOException {
        if (input.incrementToken()) {
            String t = new String(termAtt.buffer(), 0, termAtt.length());
            if (removeAccents)
                t = StringUtils.stripAccents(t);
            if (lowerCase)
                t = t.toLowerCase();
            termAtt.copyBuffer(t.toCharArray(), 0, t.length());
            return true;
        }
        return false;
    }

}