mapreduce/src/java/org/apache/hadoop/mapred/TextInputFormat.java

/**
 * 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.*;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.*;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.*;

/** An {@link InputFormat} for plain text files.  Files are broken into lines.
 * Either linefeed or carriage-return are used to signal end of line.  Keys are
 * the position in the file, and values are the line of text.. 
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public class TextInputFormat extends FileInputFormat<LongWritable, Text>
  implements JobConfigurable {

  private CompressionCodecFactory compressionCodecs = null;
  
  public void configure(JobConf conf) {
    compressionCodecs = new CompressionCodecFactory(conf);
  }
  
  protected boolean isSplitable(FileSystem fs, Path file) {
    final CompressionCodec codec = compressionCodecs.getCodec(file);
    if (null == codec) {
      return true;
    }
    return codec instanceof SplittableCompressionCodec;
  }

  public RecordReader<LongWritable, Text> getRecordReader(
                                          InputSplit genericSplit, JobConf job,
                                          Reporter reporter)
    throws IOException {
    
    reporter.setStatus(genericSplit.toString());
    return new LineRecordReader(job, (FileSplit) genericSplit);
  }
}