GradoopLabelPropagation.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.gelly.labelpropagation;

import org.apache.flink.api.java.DataSet;
import org.apache.flink.graph.Graph;
import org.apache.flink.types.NullValue;
import org.gradoop.common.model.api.entities.Edge;
import org.gradoop.common.model.api.entities.GraphHead;
import org.gradoop.common.model.api.entities.Vertex;
import org.gradoop.common.model.impl.id.GradoopId;
import org.gradoop.common.model.impl.properties.PropertyValue;
import org.gradoop.flink.algorithms.gelly.labelpropagation.functions.LPMessageFunction;
import org.gradoop.flink.algorithms.gelly.labelpropagation.functions.LPUpdateFunction;
import org.gradoop.flink.model.api.epgm.BaseGraph;
import org.gradoop.flink.model.api.epgm.BaseGraphCollection;

/**
 * Executes the label propagation integrated in Gradoop.
 *
 * @param <G>  Gradoop graph head type.
 * @param <V>  Gradoop vertex type.
 * @param <E>  Gradoop edge type.
 * @param <LG> Gradoop type of the graph.
 * @param <GC> Gradoop type of the graph collection.
 */
public class GradoopLabelPropagation<
  G extends GraphHead,
  V extends Vertex,
  E extends Edge,
  LG extends BaseGraph<G, V, E, LG, GC>,
  GC extends BaseGraphCollection<G, V, E, LG, GC>> extends LabelPropagation<G, V, E, LG, GC> {

  /**
   * Constructor
   *
   * @param maxIterations Counter to define maximal iteration for the algorithm
   * @param propertyKey   Property key to access the label value
   */
  public GradoopLabelPropagation(int maxIterations, String propertyKey) {
    super(maxIterations, propertyKey);
  }

  @Override
  protected DataSet<org.apache.flink.graph.Vertex<GradoopId, PropertyValue>>
  executeInternal(Graph<GradoopId, PropertyValue, NullValue> gellyGraph) {
    return gellyGraph.runScatterGatherIteration(
      new LPMessageFunction(), new LPUpdateFunction(), getMaxIterations())
      .getVertices();
  }
}