001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.text.nlp.namedentity;
031
032import java.util.ArrayList;
033import java.util.HashMap;
034import java.util.List;
035import java.util.Map;
036import java.util.Set;
037
038import org.openimaj.ml.annotation.ScoredAnnotation;
039import org.openimaj.text.nlp.namedentity.YagoEntityCandidateFinderFactory.YagoEntityCandidateFinder;
040import org.openimaj.text.nlp.namedentity.YagoEntityContextScorerFactory.YagoEntityContextScorer;
041import org.openimaj.text.nlp.namedentity.YagoEntityExactMatcherFactory.YagoEntityExactMatcher;
042
043/**
044 * {@link EntityAnnotator} wrapper for {@link YagoEntityExactMatcher}
045 * 
046 * @author Laurence Willmore (lgw1e10@ecs.soton.ac.uk)
047 * @author Sina Samangooei (ss@ecs.soton.ac.uk)
048 */
049public class YagoEntityCompleteAnnotator extends EntityAnnotator {
050        private YagoEntityContextScorer contextScorer;
051        private YagoEntityCandidateFinder candidateFinder;
052        private int localContextBound = 20;
053
054        /**
055         * Default constructor.
056         * 
057         * @param contextScorer
058         * @param candidateFinder
059         */
060        public YagoEntityCompleteAnnotator(YagoEntityContextScorer contextScorer,
061                        YagoEntityCandidateFinder candidateFinder)
062        {
063                super();
064                this.contextScorer = contextScorer;
065                this.candidateFinder = candidateFinder;
066        }
067
068        @Override
069        public Set<HashMap<String, Object>> getAnnotations() {
070                // Intentionally blank
071                return null;
072        }
073
074        @Override
075        public List<ScoredAnnotation<HashMap<String, Object>>> annotate(
076                        List<String> tokens)
077        {
078                final ArrayList<ScoredAnnotation<HashMap<String, Object>>> result = new ArrayList<ScoredAnnotation<HashMap<String, Object>>>();
079                // Check if any candidates are found
080                final List<List<NamedEntity>> candidates = candidateFinder
081                                .getCandidates(tokens);
082                // If none found, return an empty.
083                if (candidates.size() == 0) {
084                        return result;
085                }
086                // Use Context Scoring to disambiguate candidates
087                for (final List<NamedEntity> can : candidates) {
088                        final ArrayList<String> companies = new ArrayList<String>();
089                        for (final NamedEntity ent : can) {
090                                companies.add(ent.rootName);
091                        }
092                        // get the localised context for each list of named Entities
093                        final List<String> localContext = getLocalContext(tokens, can.get(0).startToken, can.get(0).stopToken);
094                        final Map<NamedEntity, Float> contextScores = contextScorer
095                                        .getScoresForEntityList(companies, localContext);
096                        float topScore = 0;
097                        NamedEntity resEntity = null;
098                        for (final NamedEntity entity : can) {
099                                if (contextScores.keySet().contains(entity)
100                                                && contextScores.get(entity) > topScore)
101                                {
102                                        resEntity = entity;
103                                        topScore = contextScores.get(entity);
104                                }
105                        }
106                        if (resEntity != null) {
107                                final HashMap<String, Object> annotation = new HashMap<String, Object>();
108                                annotation.put(YagoEntityContextAnnotator.SCORE, topScore);
109                                annotation.put(YagoEntityContextAnnotator.URI, resEntity.rootName);
110                                annotation.put(YagoEntityContextAnnotator.START_TOKEN,
111                                                resEntity.startToken);
112                                annotation.put(YagoEntityContextAnnotator.END_TOKEN,
113                                                resEntity.stopToken);
114                                annotation.put(YagoEntityContextAnnotator.TYPE,
115                                                resEntity.type.toString());
116                                result.add(new ScoredAnnotation<HashMap<String, Object>>(
117                                                annotation, 1));
118                        }
119                }
120                return result;
121        }
122
123        private List<String> getLocalContext(List<String> tokens, int startToken,
124                        int stopToken)
125        {
126                final int bottom = Math.max(0, startToken - localContextBound);
127                final int top = Math.min(tokens.size(), stopToken + localContextBound);
128                return tokens.subList(bottom, top);
129        }
130}