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.TaskAttemptContext; 26 27 /** 28 * Implement to output the graph after the computation. It is modeled 29 * directly after the Hadoop OutputFormat. 30 * ImmutableClassesGiraphConfiguration is available 31 * 32 * It's guaranteed that whatever parameters are set in the configuration are 33 * also going to be available in all method arguments related to this output 34 * format (context in createVertexWriter, checkOutputSpecs and 35 * getOutputCommitter; methods invoked on VertexWriter and OutputCommitter). 36 * So if backing output format relies on some parameters from configuration, 37 * you can safely set them for example in 38 * {@link #setConf(org.apache.giraph.conf.ImmutableClassesGiraphConfiguration)}. 39 * 40 * @param <I> Vertex index value 41 * @param <V> Vertex value 42 * @param <E> Edge value 43 */ 44 @SuppressWarnings("rawtypes") 45 public abstract class VertexOutputFormat< 46 I extends WritableComparable, V extends Writable, 47 E extends Writable> extends 48 OutputFormat<I, V, E> { 49 /** 50 * Create a vertex writer for a given split. The framework will call 51 * {@link VertexWriter#initialize(TaskAttemptContext)} before 52 * the split is used. 53 * 54 * @param context the information about the task 55 * @return a new vertex writer 56 * @throws IOException 57 * @throws InterruptedException 58 */ 59 public abstract VertexWriter<I, V, E> createVertexWriter( 60 TaskAttemptContext context) throws IOException, InterruptedException; 61 }