1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 package org.apache.giraph.graph; 20 21 import org.apache.hadoop.io.Writable; 22 23 /** 24 * When vertex values with the same vertex id are loaded, this 25 * class specifies how to combine their vertex values. Edges loaded will 26 * be added to the EdgeStore. 27 * 28 * @param <V> Vertex data 29 */ 30 public interface VertexValueCombiner<V extends Writable> { 31 /** 32 * Combine a vertex with the original vertex 33 * by modifying originalVertex. 34 * 35 * @param originalVertexValue Combine the other vertex into this one 36 * @param vertexValue Combine into the originalVertex. 37 */ 38 void combine(V originalVertexValue, V vertexValue); 39 }