src/edu/siu/sentise/preprocessing/StanfordCoreNLPLemmatizer.java

/*
 * Copyright (C) 2018 Southern Illinois University Carbondale, SoftSearch Lab
 *
 * Author: Amiangshu Bosu
 *
 * Licensed under GNU LESSER GENERAL PUBLIC LICENSE Version 3, 29 June 2007
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.gnu.org/licenses/lgpl.html
 *
 * 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 edu.siu.sentise.preprocessing;

import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import edu.stanford.nlp.ling.CoreAnnotations.LemmaAnnotation;
import edu.stanford.nlp.ling.CoreAnnotations.SentencesAnnotation;
import edu.stanford.nlp.ling.CoreAnnotations.TokensAnnotation;
import edu.siu.sentise.model.SentimentData;
import edu.stanford.nlp.ling.CoreLabel;
import edu.stanford.nlp.pipeline.Annotation;
import edu.stanford.nlp.pipeline.StanfordCoreNLP;
import edu.stanford.nlp.util.CoreMap;

public class StanfordCoreNLPLemmatizer  implements weka.core.stemmers.Stemmer  {

	private StanfordCoreNLP pipeline = null;
		
	public StanfordCoreNLPLemmatizer () {
	
		 Properties props = new Properties();
		  props.setProperty("annotators","tokenize, ssplit, pos, lemma");
	      pipeline = new StanfordCoreNLP(props);
	}
	
  	
	
	public  String stem(String word) 
    { 
       StringBuilder lema=new StringBuilder();
        // Create an empty Annotation just with the given text 
        Annotation document = new Annotation(word); 
        // run all Annotators on this text 
        pipeline.annotate(document); 
        // Iterate over all of the sentences found 
        List<CoreMap> sentences = document.get(SentencesAnnotation.class); 
        for(CoreMap sentence: sentences) { 
            // Iterate over all tokens in a sentence 
            for (CoreLabel token: sentence.get(TokensAnnotation.class)) { 
                // Retrieve and add the lemma for each word into the 
                // list of lemmas 
            	//System.out.println(token.value().toString());
            	if(!token.value().toString().endsWith("s"))
					lema.append(token.value().toString());
			  else
                 lema.append((token.get(LemmaAnnotation.class)));
                
            } 
        } 
        return lema.toString(); 
    }



	@Override
	public String getRevision() {
		// TODO Auto-generated method stub
		return "$Revision: 8034 $";
	}
}