org.apache.hadoop.mapreduce.lib.input
Class DelegatingInputFormat<K,V>

java.lang.Object
  extended by org.apache.hadoop.mapreduce.InputFormat<K,V>
      extended by org.apache.hadoop.mapreduce.lib.input.DelegatingInputFormat<K,V>

@InterfaceAudience.Private
@InterfaceStability.Unstable
public class DelegatingInputFormat<K,V>
extends InputFormat<K,V>

An InputFormat that delegates behavior of paths to multiple other InputFormats.

See Also:
MultipleInputs.addInputPath(Job, Path, Class, Class)

Constructor Summary
DelegatingInputFormat()
           
 
Method Summary
 RecordReader<K,V> createRecordReader(InputSplit split, TaskAttemptContext context)
          Create a record reader for a given split.
 List<InputSplit> getSplits(JobContext job)
          Logically split the set of input files for the job.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DelegatingInputFormat

public DelegatingInputFormat()
Method Detail

getSplits

public List<InputSplit> getSplits(JobContext job)
                           throws IOException,
                                  InterruptedException
Description copied from class: InputFormat
Logically split the set of input files for the job.

Each InputSplit is then assigned to an individual Mapper for processing.

Note: The split is a logical split of the inputs and the input files are not physically split into chunks. For e.g. a split could be <input-file-path, start, offset> tuple. The InputFormat also creates the RecordReader to read the InputSplit.

Specified by:
getSplits in class InputFormat<K,V>
Parameters:
job - job configuration.
Returns:
an array of InputSplits for the job.
Throws:
IOException
InterruptedException

createRecordReader

public RecordReader<K,V> createRecordReader(InputSplit split,
                                            TaskAttemptContext context)
                                     throws IOException,
                                            InterruptedException
Description copied from class: InputFormat
Create a record reader for a given split. The framework will call RecordReader.initialize(InputSplit, TaskAttemptContext) before the split is used.

Specified by:
createRecordReader in class InputFormat<K,V>
Parameters:
split - the split to be read
context - the information about the task
Returns:
a new record reader
Throws:
IOException
InterruptedException


Copyright © 2009 The Apache Software Foundation