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.io; 20 21 import org.apache.hadoop.io.Writable; 22 import org.apache.hadoop.io.WritableComparable; 23 import org.apache.hadoop.mapreduce.InputSplit; 24 import org.apache.hadoop.mapreduce.TaskAttemptContext; 25 26 import java.io.IOException; 27 28 /** 29 * Vertex input format that only allows setting vertex id and value. It can 30 * be used in conjunction with {@link EdgeInputFormat}. 31 * 32 * @param <I> Vertex id 33 * @param <V> Vertex value 34 */ 35 public abstract class VertexValueInputFormat<I extends WritableComparable, 36 V extends Writable> extends VertexInputFormat<I, V, Writable> { 37 /** 38 * Create a {@link VertexValueReader} for a given split. The framework will 39 * call {@link VertexValueReader#initialize(InputSplit, 40 * TaskAttemptContext)} before the split is used. 41 * 42 * @param split The split to be read 43 * @param context The information about the task 44 * @return A new vertex value reader 45 * @throws IOException 46 */ 47 public abstract VertexValueReader<I, V> createVertexValueReader( 48 InputSplit split, TaskAttemptContext context) throws IOException; 49 50 @Override 51 public final VertexReader<I, V, Writable> createVertexReader( 52 InputSplit split, TaskAttemptContext context) throws IOException { 53 return createVertexValueReader(split, context); 54 } 55 }