com.bakdata.deduplication.clustering.RefinedTransitiveClosure Maven / Gradle / Ivy

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/*
 * The MIT License
 *
 * Copyright (c) 2018 bakdata GmbH
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
package com.bakdata.deduplication.clustering;

import com.bakdata.deduplication.classifier.ClassifiedCandidate;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
import lombok.Builder;
import lombok.NonNull;
import lombok.Value;

@Value
@Builder
public class RefinedTransitiveClosure, T, I extends Comparable> implements Clustering {
    @NonNull
    RefineCluster refineCluster;

    @NonNull
    Map> oldClusterIndex;

    @NonNull
    TransitiveClosure closure;

    @NonNull
    Function idExtractor;

    @java.beans.ConstructorProperties({"refineCluster", "oldClusterIndex", "closure", "idExtractor"})
    RefinedTransitiveClosure(final @NonNull RefineCluster refineCluster,
        final Map> oldClusterIndex, final TransitiveClosure closure,
        final @NonNull Function idExtractor) {
        this.refineCluster = refineCluster;
        this.oldClusterIndex = oldClusterIndex != null ? oldClusterIndex : new HashMap<>();
        this.closure = closure != null ? closure
            : new TransitiveClosure<>(idExtractor, refineCluster.getClusterIdGenerator(), new HashMap<>());
        this.idExtractor = idExtractor;
    }

    @Override
    public List> cluster(final List> classified) {
        final List> transitiveClosure = this.closure.cluster(classified);
        final List> refinedClusters = this.refineCluster.refine(transitiveClosure, classified);

        final Collection> changedClusters = new ArrayList<>();
        for (final Cluster refinedCluster : refinedClusters) {
            for (final T element : refinedCluster.getElements()) {
                final I id = this.idExtractor.apply(element);
                final Cluster oldCluster = this.oldClusterIndex.put(id, refinedCluster);
                if (oldCluster == null || !this.getClusterId(oldCluster).equals(this.getClusterId(refinedCluster))) {
                    changedClusters.add(refinedCluster);
                }
            }
        }

        // return the changed clusters but remove multiple occurences of the same cluster
        return changedClusters.stream()
                .collect(Collectors.groupingBy(this::getClusterId))
                .values()
                .stream()
                .map(clusters -> clusters.get(0))
                .collect(Collectors.toList());
    }

    private I getClusterId(final Cluster cluster) {
        return this.idExtractor.apply(cluster.get(0));
    }

    @Override
    public Function, C> getClusterIdGenerator() {
        return this.closure.getClusterIdGenerator();
    }

}