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 java.io.IOException; 22 23 import org.apache.hadoop.io.Writable; 24 import org.apache.hadoop.io.WritableComparable; 25 import org.apache.hadoop.mapreduce.InputSplit; 26 import org.apache.hadoop.mapreduce.TaskAttemptContext; 27 28 /** 29 * Use this to load data for a BSP application. Note that the InputSplit must 30 * also implement Writable. The InputSplits will determine the partitioning of 31 * vertices across the mappers, so keep that in consideration when implementing 32 * getSplits(). Provides access to ImmutableClassesGiraphConfiguration. 33 * 34 * It's guaranteed that whatever parameters are set in the configuration are 35 * also going to be available in all method arguments related to this input 36 * format (context in getSplits and createVertexReader; methods invoked on 37 * VertexReader). So if backing input format relies on some parameters from 38 * configuration, you can safely set them for example in 39 * {@link #setConf(org.apache.giraph.conf.ImmutableClassesGiraphConfiguration)}. 40 * 41 * @param <I> Vertex id 42 * @param <V> Vertex value 43 * @param <E> Edge value 44 */ 45 @SuppressWarnings("rawtypes") 46 public abstract class VertexInputFormat<I extends WritableComparable, 47 V extends Writable, E extends Writable> extends GiraphInputFormat<I, V, E> { 48 /** 49 * Create a vertex reader for a given split. Guaranteed to have been 50 * configured with setConf() prior to use. The framework will also call 51 * {@link VertexReader#initialize(InputSplit, TaskAttemptContext)} before 52 * the split is used. 53 * 54 * @param split the split to be read 55 * @param context the information about the task 56 * @return a new record reader 57 * @throws IOException 58 */ 59 public abstract VertexReader<I, V, E> createVertexReader( 60 InputSplit split, 61 TaskAttemptContext context) throws IOException; 62 }