001/** 
002 * Copyright (c) 2007-2008, Regents of the University of Colorado 
003 * All rights reserved.
004 * 
005 * Redistribution and use in source and binary forms, with or without
006 * modification, are permitted provided that the following conditions are met:
007 * 
008 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 
009 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 
010 * Neither the name of the University of Colorado at Boulder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 
011 * 
012 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
013 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
014 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
015 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
016 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
017 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
018 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
019 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
020 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
021 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
022 * POSSIBILITY OF SUCH DAMAGE. 
023 */
024package org.cleartk.ml.feature.extractor;
025
026import java.util.Collections;
027import java.util.List;
028
029import org.apache.uima.jcas.JCas;
030import org.apache.uima.jcas.tcas.Annotation;
031import org.cleartk.ml.Feature;
032import org.cleartk.util.AnnotationUtil;
033import org.apache.uima.fit.util.JCasUtil;
034
035/**
036 * <br>
037 * Copyright (c) 2007-2008, Regents of the University of Colorado <br>
038 * All rights reserved.
039 * 
040 * 
041 * @author Philip Ogren This class was initially copied from DistanceExtractor and was modified in
042 *         two ways:
043 *         <ul>
044 *         <li>the distance between annotations will be negative if the first annotation comes after
045 *         the second</li>
046 *         <li>zero will only be returned if the two annotations overlap. Adjacent annotations will
047 *         have a distance of |1|.</li>
048 *         </ul>
049 */
050
051public class DirectedDistanceExtractor<T extends Annotation, U extends Annotation> implements
052    FeatureExtractor2<T, U> {
053  String name;
054
055  Class<? extends Annotation> unitClass;
056
057  public DirectedDistanceExtractor(String name, Class<? extends Annotation> unitClass) {
058    this.name = name;
059    this.unitClass = unitClass;
060  }
061
062  public List<Feature> extract(JCas jCas, Annotation annotation1, Annotation annotation2) {
063    String featureName = Feature.createName(this.name, "DDistance", this.unitClass.getSimpleName());
064
065    Annotation firstAnnotation, secondAnnotation;
066    boolean negate = false;
067    if (annotation1.getBegin() <= annotation2.getBegin()) {
068      firstAnnotation = annotation1;
069      secondAnnotation = annotation2;
070    } else {
071      firstAnnotation = annotation2;
072      secondAnnotation = annotation1;
073      negate = true;
074    }
075
076    int featureValue = 0;
077
078    if (AnnotationUtil.overlaps(annotation1, annotation2)) {
079      featureValue = 0;
080    } else {
081      List<? extends Annotation> annotations = JCasUtil.selectCovered(
082          jCas,
083          unitClass,
084          firstAnnotation.getEnd(),
085          secondAnnotation.getBegin());
086      featureValue = annotations.size() + 1;
087    }
088    if (negate)
089      featureValue = -featureValue;
090
091    return Collections.singletonList(new Feature(featureName, featureValue));
092  }
093}