Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.godhuli.rhipe; import java.io.*; import org.apache.hadoop.fs.*; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.compress.*; import org.apache.hadoop.mapred.*; import java.util.List; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import java.io.IOException; import org.apache.hadoop.io.compress.CompressionCodec; import org.apache.hadoop.io.compress.CompressionCodecFactory; import org.apache.hadoop.mapreduce.InputFormat; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.input.NLineInputFormat; import org.apache.hadoop.mapreduce.InputSplit; import org.apache.hadoop.mapreduce.JobContext; import org.apache.hadoop.mapreduce.RecordReader; import org.apache.hadoop.mapreduce.TaskAttemptContext; ///////////////////////////////////////////////////////////// // A wrapper class around NLineInputFormat // // Useful for simulations, as opposed to reading to hadoop // ///////////////////////////////////////////////////////////// public class RNLineInputFormat extends FileInputFormat<RHNumeric, RHText> { // To change split length // Adjust mapreduce.input.lineinputformat.linespermap private static org.apache.hadoop.mapreduce.lib.input.NLineInputFormat _nlf; public RNLineInputFormat() { _nlf = new org.apache.hadoop.mapreduce.lib.input.NLineInputFormat(); } public RecordReader<RHNumeric, RHText> createRecordReader(InputSplit genericSplit, TaskAttemptContext context) throws IOException { context.setStatus(genericSplit.toString()); return new RXLineRecordReader(); } public List<InputSplit> getSplits(JobContext job) throws IOException { return _nlf.getSplits(job); } public static List<org.apache.hadoop.mapreduce.lib.input.FileSplit> getSplitsForFile(FileStatus status, Configuration conf, int numLinesPerSplit) throws IOException { return _nlf.getSplitsForFile(status, conf, numLinesPerSplit); } }