CreateNewVertex.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.dataintegration.transformation.impl.functions;

import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.gradoop.common.model.api.entities.VertexFactory;
import org.gradoop.common.model.impl.id.GradoopId;
import org.gradoop.common.model.impl.pojo.EPGMVertex;
import org.gradoop.common.model.impl.properties.PropertyValue;

import java.util.Collections;
import java.util.List;

/**
 * Creates a new {@link EPGMVertex} containing the given attribute {@link PropertyValue} and its origin.
 */
public class CreateNewVertex implements MapFunction<Tuple2<PropertyValue, GradoopId>, Tuple2<EPGMVertex, List<GradoopId>>> {
  /**
   * The new vertex label.
   */
  private final String newVertexLabel;

  /**
   * The new property key
   */
  private final String newPropertyName;

  /**
   * The Factory the vertices are created with.
   */
  private final VertexFactory<EPGMVertex> vertexFactory;

  /**
   * Reduce object instantiation.
   */
  private final Tuple2<EPGMVertex, List<GradoopId>> reuseTuple;

  /**
   * The constructor for creating new vertices with their origin Ids.
   *
   * @param factory The Factory the vertices are created with.
   * @param newVertexLabel  The new vertex Label.
   * @param newPropertyName The new property key.
   */
  public CreateNewVertex(VertexFactory<EPGMVertex> factory, String newVertexLabel, String newPropertyName) {
    this.vertexFactory = factory;
    this.newVertexLabel = newVertexLabel;
    this.newPropertyName = newPropertyName;

    this.reuseTuple = new Tuple2<>();
  }

  @Override
  public Tuple2<EPGMVertex, List<GradoopId>> map(Tuple2<PropertyValue, GradoopId> tuple) {
    EPGMVertex vertex = vertexFactory.createVertex(newVertexLabel);
    vertex.setProperty(newPropertyName, tuple.f0);

    reuseTuple.f0 = vertex;
    reuseTuple.f1 = Collections.singletonList(tuple.f1);

    return reuseTuple;
  }
}