EdgeTargetUpdateJoin.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.model.impl.functions.epgm;

import org.apache.flink.api.common.functions.JoinFunction;
import org.apache.flink.api.java.functions.FunctionAnnotation;
import org.apache.flink.api.java.tuple.Tuple2;
import org.gradoop.common.model.api.entities.Edge;
import org.gradoop.common.model.impl.id.GradoopId;

/**
 * Joins edges with a Tuple2 that contains the id of the original edge
 * target in its first field and the id of the new edge target vertex in its second.<p>
 * The output is an edge with updated target id.<p>
 * If the tuple is {@code null}, then the edge is not changed.
 *
 * @param <E> edge type
 */
@FunctionAnnotation.NonForwardedFieldsFirst("targetId")
@FunctionAnnotation.ReadFieldsSecond("*")
public class EdgeTargetUpdateJoin<E extends Edge>
  implements JoinFunction<E, Tuple2<GradoopId, GradoopId>, E> {

  @Override
  public E join(E edge, Tuple2<GradoopId, GradoopId> mapping) {
    if (mapping != null) {
      edge.setTargetId(mapping.f1);
    }
    return edge;
  }
}