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.edge; 20 21 import org.apache.hadoop.io.NullWritable; 22 import org.apache.hadoop.io.WritableComparable; 23 24 /** 25 * An edge that has no value. 26 * 27 * @param <I> Vertex ID 28 */ 29 public class EdgeNoValue<I extends WritableComparable> 30 implements ReusableEdge<I, NullWritable> { 31 /** Target vertex id */ 32 private I targetVertexId = null; 33 34 /** Empty constructor */ 35 EdgeNoValue() { } 36 37 /** 38 * Constructor with target vertex ID. Don't call, use EdgeFactory instead. 39 * 40 * @param targetVertexId vertex ID 41 */ 42 EdgeNoValue(I targetVertexId) { 43 this.targetVertexId = targetVertexId; 44 } 45 46 @Override 47 public void setTargetVertexId(I targetVertexId) { 48 this.targetVertexId = targetVertexId; 49 } 50 51 @Override 52 public void setValue(NullWritable value) { 53 // do nothing 54 } 55 56 @Override 57 public I getTargetVertexId() { 58 return targetVertexId; 59 } 60 61 @Override 62 public NullWritable getValue() { 63 return NullWritable.get(); 64 } 65 66 @Override 67 public String toString() { 68 return "(targetVertexId = " + targetVertexId + ")"; 69 } 70 }