org.gradoop.flink.algorithms.fsm.transactional.tle.functions.SingleEdgeEmbeddings.java Source code

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Here is the source code for org.gradoop.flink.algorithms.fsm.transactional.tle.functions.SingleEdgeEmbeddings.java

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/**
 * Copyright  2014 - 2018 Leipzig University (Database Research Group)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.gradoop.flink.algorithms.fsm.transactional.tle.functions;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.gradoop.flink.algorithms.fsm.transactional.common.FSMConfig;
import org.gradoop.flink.algorithms.fsm.transactional.tle.canonicalization.CanonicalLabeler;
import org.gradoop.flink.algorithms.fsm.transactional.tle.pojos.Embedding;
import org.gradoop.flink.algorithms.fsm.transactional.tle.pojos.FSMEdge;
import org.gradoop.flink.algorithms.fsm.transactional.tle.pojos.FSMGraph;

import java.io.Serializable;
import java.util.List;
import java.util.Map;

/**
 * Superclass of flatmap functions extracting distinct single-edge subgraphs
 * and all embeddings from a graph.
 */
public abstract class SingleEdgeEmbeddings implements Serializable {

    /**
     * graph labeler
     */
    protected CanonicalLabeler canonicalLabeler;

    /**
     * Constructor.
     *
     * @param fsmConfig FSM configuration
     */
    public SingleEdgeEmbeddings(FSMConfig fsmConfig) {
        canonicalLabeler = new CanonicalLabeler(fsmConfig.isDirected());
    }

    /**
     * Finds all embeddings.
     *
     * @param graph graph
     * @return 1-edge embeddings
     */
    protected Map<String, List<Embedding>> createEmbeddings(FSMGraph graph) {

        Map<Integer, String> vertices = graph.getVertices();
        Map<String, List<Embedding>> subgraphEmbeddings = Maps.newHashMap();

        for (Map.Entry<Integer, FSMEdge> entry : graph.getEdges().entrySet()) {

            FSMEdge edge = entry.getValue();
            int sourceId = edge.getSourceId();
            int targetId = edge.getTargetId();

            Map<Integer, String> incidentVertices = Maps.newHashMapWithExpectedSize(2);

            incidentVertices.put(sourceId, vertices.get(sourceId));

            if (sourceId != targetId) {
                incidentVertices.put(targetId, vertices.get(targetId));
            }

            Map<Integer, FSMEdge> singleEdge = Maps.newHashMapWithExpectedSize(1);
            singleEdge.put(entry.getKey(), edge);

            Embedding embedding = new Embedding(incidentVertices, singleEdge);

            String subgraph = canonicalLabeler.label(embedding);

            List<Embedding> embeddings = subgraphEmbeddings.get(subgraph);

            if (embeddings == null) {
                subgraphEmbeddings.put(subgraph, Lists.newArrayList(embedding));
            } else {
                embeddings.add(embedding);
            }
        }

        return subgraphEmbeddings;
    }
}