001/** 
002 * Copyright (c) 2007-2009, 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.feature.syntax;
025
026import java.util.Collections;
027import java.util.List;
028
029import org.apache.uima.jcas.JCas;
030import org.cleartk.ml.Feature;
031import org.cleartk.ml.feature.extractor.CleartkExtractorException;
032import org.cleartk.ml.feature.extractor.FeatureExtractor1;
033import org.cleartk.syntax.constituent.type.TreebankNode;
034import org.apache.uima.fit.util.JCasUtil;
035
036import com.google.common.collect.Lists;
037
038/**
039 * <br>
040 * Copyright (c) 2007-2009, Regents of the University of Colorado <br>
041 * All rights reserved.
042 * 
043 * 
044 * @author Philipp Wetzler
045 */
046public class SiblingExtractor implements FeatureExtractor1<TreebankNode> {
047
048  public SiblingExtractor(int offset, FeatureExtractor1<TreebankNode> subExtractor) {
049    this.offset = offset;
050    this.subExtractor = subExtractor;
051
052    if (offset < 0) {
053      if (Math.abs(offset) > 1)
054        this.name = String.format("%dLeftSibling");
055      else
056        this.name = "LeftSibling";
057    } else if (offset > 0) {
058      if (Math.abs(offset) > 1)
059        this.name = String.format("%dRightSibling");
060      else
061        this.name = "RightSibling";
062    } else {
063      this.name = "";
064    }
065  }
066
067
068  public List<Feature> extract(JCas jCas, TreebankNode node)
069      throws CleartkExtractorException {
070    TreebankNode parent = node.getParent();
071
072    if (parent == null)
073      return Collections.emptyList();
074
075    List<TreebankNode> children = Lists.newArrayList(JCasUtil.select(
076        parent.getChildren(),
077        TreebankNode.class));
078    int index = children.indexOf(node);
079    int siblingIndex = index + offset;
080
081    if (siblingIndex < 0 || siblingIndex >= children.size())
082      return Collections.emptyList();
083
084    TreebankNode sibling = children.get(siblingIndex);
085
086    List<Feature> features = subExtractor.extract(jCas, sibling);
087    for (Feature feature : features) {
088      feature.setName(Feature.createName(name, feature.getName()));
089    }
090
091    return features;
092  }
093
094  private int offset;
095
096  private String name;
097
098  private FeatureExtractor1<TreebankNode> subExtractor;
099
100}