com.reactivetechnologies.analytics.lucene.TextInstanceFilter.java Source code

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Here is the source code for com.reactivetechnologies.analytics.lucene.TextInstanceFilter.java

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/* ============================================================================
*
* FILE: TextInstanceFilter.java
*
The MIT License (MIT)
    
Copyright (c) 2016 Sutanu Dalui
    
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
    
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
    
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*
* ============================================================================
*/
package com.reactivetechnologies.analytics.lucene;

import org.springframework.util.StringUtils;

import weka.core.Instances;
import weka.core.Utils;
import weka.core.stemmers.NullStemmer;
import weka.filters.unsupervised.attribute.StringToWordVector;

public class TextInstanceFilter extends StringToWordVector {

    /**
     * 
     */
    private static final long serialVersionUID = -2252812893678029864L;

    private TextInstanceFilter() {
        super();
    }

    /**
     * Converts String attributes into a set of attributes representing word occurrence information from the text contained in the strings. 
     * The set of words (attributes) is determined by the first batch filtered (typically training data). Uses a Lucene analyzer to tokenize
     * the string. NOTE: The text string should either be the first or last attribute
     * @param dataRaw
     * @param opts
     * @param isLast - whether last attribute is the text to be filtered, else first
     * @return
     * @throws Exception
     * @see {@linkplain StringToWordVector}
     */
    public static Instances filter(Instances dataRaw, String opts, boolean isLast) throws Exception {
        TextInstanceFilter filter = new TextInstanceFilter();
        if (StringUtils.hasText(opts)) {
            filter.setOptions(Utils.splitOptions(opts));
        }
        filter.setTokenizer(new InstanceTokenizer());
        filter.setUseStoplist(false);//ignore any other stop list
        filter.setStemmer(new NullStemmer());//ignore any other stemmer
        filter.setInputFormat(dataRaw);
        filter.setAttributeIndices(isLast ? "last" : "first");
        filter.setDoNotOperateOnPerClassBasis(true);
        filter.setWordsToKeep(10000);
        return useFilter(dataRaw, filter);
    }

}