CreateFusedVertex.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.operators.fusion.functions;

import org.apache.flink.api.common.functions.CrossFunction;
import org.apache.flink.api.java.functions.FunctionAnnotation;
import org.gradoop.common.model.impl.id.GradoopId;
import org.gradoop.common.model.impl.pojo.EPGMVertex;
import org.gradoop.common.model.impl.pojo.EPGMGraphHead;

/**
 *
 * Creates the fused vertex from the collection of the graph head of the pattern graph element.
 * The new vertex is stored as an occurrence of the searchGraph
 *
 */
@FunctionAnnotation.ForwardedFieldsFirst("id")
@FunctionAnnotation.ForwardedFieldsSecond("label;properties")
public class CreateFusedVertex implements CrossFunction<EPGMGraphHead, EPGMGraphHead, EPGMVertex> {

  /**
   * Basic vertex reused each time. It'll be the fused vertex
   */
  private static final EPGMVertex REUSABLE_VERTEX = new EPGMVertex();

  /**
   * newly generated vertex id for the new vertex
   */
  private GradoopId newVertexId;

  /**
   * Given the new vertex Id, it generates the joiner generating the new vertex
   * @param newVertexId   new vertex Id
   */
  public CreateFusedVertex(GradoopId newVertexId) {
    this.newVertexId = newVertexId;
  }

  @Override
  public EPGMVertex cross(EPGMGraphHead searchGraphHead, EPGMGraphHead patternGraphSeachHead) {
    REUSABLE_VERTEX.setLabel(patternGraphSeachHead.getLabel());
    REUSABLE_VERTEX.setProperties(patternGraphSeachHead.getProperties());
    REUSABLE_VERTEX.setId(newVertexId);
    REUSABLE_VERTEX.addGraphId(searchGraphHead.getId());
    return REUSABLE_VERTEX;
  }
}