001/** 
002 * Copyright (c) 2010, 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.ArrayList;
027import java.util.Collections;
028import java.util.List;
029
030import org.apache.uima.jcas.JCas;
031import org.cleartk.ml.Feature;
032import org.cleartk.ml.feature.extractor.FeatureExtractor2;
033import org.cleartk.syntax.constituent.type.TreebankNode;
034
035/**
036 * <br>
037 * Copyright (c) 2010, Regents of the University of Colorado <br>
038 * All rights reserved.
039 * 
040 * @author Steven Bethard
041 */
042public class TargetPathExtractor implements FeatureExtractor2<TreebankNode, TreebankNode>  {
043  public List<Feature> extract(JCas jCas, TreebankNode source, TreebankNode target) {
044    List<TreebankNode> sourceToRoot = this.pathToRoot(source);
045    List<TreebankNode> targetToRoot = this.pathToRoot(target);
046    // TreebankNode commonParent = null;
047    while (!sourceToRoot.isEmpty() && !targetToRoot.isEmpty()
048        && sourceToRoot.get(sourceToRoot.size() - 1) == targetToRoot.get(targetToRoot.size() - 1)) {
049      // commonParent = sourceToRoot.get(sourceToRoot.size() - 1);
050      sourceToRoot.remove(sourceToRoot.size() - 1);
051      targetToRoot.remove(targetToRoot.size() - 1);
052    }
053    String value = this.toTagString(targetToRoot, ">");
054    return Collections.singletonList(new Feature("TargetPath", value));
055  }
056
057  private List<TreebankNode> pathToRoot(TreebankNode leaf) {
058    List<TreebankNode> result = new ArrayList<TreebankNode>();
059    TreebankNode curr = leaf;
060    while (curr != null) {
061      result.add(curr);
062      curr = curr.getParent();
063    }
064    return result;
065  }
066
067  private String toTagString(List<TreebankNode> nodes, String join) {
068    StringBuilder builder = new StringBuilder();
069    for (TreebankNode node : nodes) {
070      if (builder.length() > 0) {
071        builder.append(join);
072      }
073      builder.append(node.getNodeType());
074    }
075    return builder.toString();
076  }
077}