| /** |
| * 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.apache.hadoop.mapred; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.io.BytesWritable; |
| import org.apache.hadoop.io.LongWritable; |
| import org.apache.hadoop.io.compress.CompressionCodec; |
| import org.apache.hadoop.io.compress.CompressionCodecFactory; |
| |
| /** |
| * FixedLengthInputFormat is an input format used to read input files |
| * which contain fixed length records. The content of a record need not be |
| * text. It can be arbitrary binary data. Users must configure the record |
| * length property by calling: |
| * FixedLengthInputFormat.setRecordLength(conf, recordLength);<br><br> or |
| * conf.setInt(FixedLengthInputFormat.FIXED_RECORD_LENGTH, recordLength); |
| * <br><br> |
| * @see FixedLengthRecordReader |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Stable |
| public class FixedLengthInputFormat |
| extends FileInputFormat<LongWritable, BytesWritable> |
| implements JobConfigurable { |
| |
| private CompressionCodecFactory compressionCodecs = null; |
| |
| public static final String FIXED_RECORD_LENGTH = |
| "fixedlengthinputformat.record.length"; |
| |
| /** |
| * Set the length of each record |
| * @param conf configuration |
| * @param recordLength the length of a record |
| */ |
| public static void setRecordLength(Configuration conf, int recordLength) { |
| conf.setInt(FIXED_RECORD_LENGTH, recordLength); |
| } |
| |
| /** |
| * Get record length value |
| * @param conf configuration |
| * @return the record length, zero means none was set |
| */ |
| public static int getRecordLength(Configuration conf) { |
| return conf.getInt(FIXED_RECORD_LENGTH, 0); |
| } |
| |
| @Override |
| public void configure(JobConf conf) { |
| compressionCodecs = new CompressionCodecFactory(conf); |
| } |
| |
| @Override |
| public RecordReader<LongWritable, BytesWritable> |
| getRecordReader(InputSplit genericSplit, JobConf job, Reporter reporter) |
| throws IOException { |
| reporter.setStatus(genericSplit.toString()); |
| int recordLength = getRecordLength(job); |
| if (recordLength <= 0) { |
| throw new IOException("Fixed record length " + recordLength |
| + " is invalid. It should be set to a value greater than zero"); |
| } |
| return new FixedLengthRecordReader(job, (FileSplit)genericSplit, |
| recordLength); |
| } |
| |
| @Override |
| protected boolean isSplitable(FileSystem fs, Path file) { |
| final CompressionCodec codec = compressionCodecs.getCodec(file); |
| return(null == codec); |
| } |
| |
| } |