RelaxedStringMatchSieve.java

//Dstl (c) Crown Copyright 2017
package uk.gov.dstl.baleen.annotators.coreference.impl.sieves;

import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import org.apache.uima.jcas.JCas;

import uk.gov.dstl.baleen.annotators.coreference.impl.data.Cluster;
import uk.gov.dstl.baleen.annotators.coreference.impl.data.Mention;
import uk.gov.dstl.baleen.annotators.coreference.impl.data.MentionType;

/**
 * String matching which is more easily satisfied than exact matching.
 */
public class RelaxedStringMatchSieve extends AbstractCoreferenceSieve {

	private static final Set<String> EXCLUDED = new HashSet<>(Arrays.asList("that", "there"));

	/**
	 * Constructor for RelaxedStringMatchSieve
	 */
	public RelaxedStringMatchSieve(JCas jCas, List<Cluster> clusters, List<Mention> mentions) {
		super(jCas, clusters, mentions);
	}

	@Override
	public void sieve() {
		// Text says nominal mention, we assume that to be mean Entity
		List<Mention> mentions = getMentionsWithHead(MentionType.ENTITY).stream()
				.filter(m -> !EXCLUDED.contains(m.getHead().toLowerCase()))
				.collect(Collectors.toList());


		for (int i = 0; i < mentions.size(); i++) {
			final Mention a = mentions.get(i);

			for (int j = i + 1; j < mentions.size(); j++) {
				final Mention b = mentions.get(j);
				
				if (a.getHead().equalsIgnoreCase(b.getHead())) {
					addToCluster(a, b);
				}
			}
		}
	}
}