TFSMSubgraphOnly.java

/*
 * Copyright © 2014 - 2021 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 org.apache.flink.api.common.functions.MapFunction;
import org.gradoop.flink.algorithms.fsm.transactional.tle.tuples.TFSMSubgraph;
import org.gradoop.flink.algorithms.fsm.transactional.tle.tuples.TFSMSubgraphEmbeddings;

/**
 * {@code (graphId, size, canonicalLabel, embeddings) => (canonicalLabel, frequency=1, sample embedding)}
 */
public class TFSMSubgraphOnly implements MapFunction<TFSMSubgraphEmbeddings, TFSMSubgraph> {

  /**
   * Reuse tuple to avoid instantiations.
   */
  private final TFSMSubgraph reuseTuple = new TFSMSubgraph(null, 1L, null);

  @Override
  public TFSMSubgraph map(
    TFSMSubgraphEmbeddings subgraphEmbeddings) throws Exception {

    reuseTuple
      .setCanonicalLabel(subgraphEmbeddings.getCanonicalLabel());

    reuseTuple
      .setEmbedding(subgraphEmbeddings.getEmbeddings().iterator().next());

    return reuseTuple;
  }
}