CrfClassificationAnnotator.java

/**
 * 
 */
package com.maalaang.comtwitter.uima.annotator;

import java.io.FileInputStream;
import java.io.InputStream;
import java.io.ObjectInputStream;

import org.apache.uima.UimaContext;
import org.apache.uima.analysis_component.JCasAnnotator_ImplBase;
import org.apache.uima.analysis_engine.AnalysisEngineProcessException;
import org.apache.uima.cas.FSIterator;
import org.apache.uima.jcas.JCas;
import org.apache.uima.jcas.tcas.Annotation;
import org.apache.uima.resource.ResourceInitializationException;
import org.apache.uima.util.Level;
import org.apache.uima.util.Logger;

import cc.mallet.fst.CRF;
import cc.mallet.pipe.Pipe;
import cc.mallet.types.ArraySequence;
import cc.mallet.types.Instance;

import com.maalaang.omtwitter.uima.type.TokenAnnotation;

/**
 * @author Sangwon Park
 *
 */
public class CrfClassificationAnnotator extends JCasAnnotator_ImplBase {
	private final String PARAM_CRF_MODEL_FILE = "crfModelFile";
	
	private	CRF crf = null;
	private Pipe pipe = null;
	private Logger logger = null;
	
	public void initialize(UimaContext aContext) throws ResourceInitializationException {
		super.initialize(aContext);
		
		logger = aContext.getLogger();
		
		try {
			String crfModel = (String)aContext.getConfigParameterValue(PARAM_CRF_MODEL_FILE);
			InputStream is = getClass().getClassLoader().getResourceAsStream(crfModel);
			if (is == null) {
				is = new FileInputStream(crfModel);
			}
			ObjectInputStream ois = new ObjectInputStream(is);
			crf = (CRF)ois.readObject();
			pipe = crf.getInputPipe();
			pipe.setTargetProcessing(false);
			
			ois.close();
//			fis.close();
			
		} catch (Exception e) {
			logger.log(Level.SEVERE, e.getMessage());
			throw new ResourceInitializationException(e);
		}		
		
	}

	public void process(JCas aJCas) throws AnalysisEngineProcessException {
		FSIterator<Annotation> it = aJCas.getAnnotationIndex(TokenAnnotation.type).iterator();
		int size = aJCas.getAnnotationIndex(TokenAnnotation.type).size();
		
		String[][] data = new String[2][size];
		
		int i = 0;
		while (it.hasNext()) {
			TokenAnnotation tokenAnnotation = (TokenAnnotation)it.next();
			data[0][i] = tokenAnnotation.getCoveredText();
			data[1][i] = tokenAnnotation.getPosTag();
			i++;
		}
		
		Instance inst = new Instance(data, null, null, null);
		
		@SuppressWarnings("unchecked")
		ArraySequence<String> label = (ArraySequence<String>) crf.label(inst).getTarget();
		
		it.moveToFirst();
		i = 0;
		while (it.hasNext()) {
			TokenAnnotation tokenAnnotation = (TokenAnnotation)it.next();
			String strLabel = label.get(i);
			tokenAnnotation.setEntityLabel(strLabel);
			i++;
		}
	}
}