org.apache.hadoop.mapred.lib

Class LazyOutputFormat<K,V>

java.lang.Object

org.apache.hadoop.mapred.lib.FilterOutputFormat<K,V>

org.apache.hadoop.mapred.lib.LazyOutputFormat<K,V>

All Implemented Interfaces:

OutputFormat<K,V>

@InterfaceAudience.Public
 @InterfaceStability.Stable
public class LazyOutputFormat<K,V>
extends FilterOutputFormat<K,V>

A Convenience class that creates output lazily.

Field Summary

Fields inherited from class org.apache.hadoop.mapred.lib.FilterOutputFormat

baseOut

Constructor Summary

Constructors

Constructor and Description
LazyOutputFormat()

Method Summary

Modifier and Type	Method and Description
void	checkOutputSpecs(FileSystem ignored, JobConf job) Check for validity of the output-specification for the job.
RecordWriter<K,V>	getRecordWriter(FileSystem ignored, JobConf job, String name, Progressable progress) Get the RecordWriter for the given job.
static void	setOutputFormatClass(JobConf job, Class<? extends OutputFormat> theClass) Set the underlying output format for LazyOutputFormat.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LazyOutputFormat

public LazyOutputFormat()

Method Detail

setOutputFormatClass

public static void setOutputFormatClass(JobConf job,
                                        Class<? extends OutputFormat> theClass)

Set the underlying output format for LazyOutputFormat.

Parameters:

job - the JobConf to modify

theClass - the underlying class

getRecordWriter

public RecordWriter<K,V> getRecordWriter(FileSystem ignored,
                                         JobConf job,
                                         String name,
                                         Progressable progress)
                                  throws IOException

Description copied from interface: OutputFormat

Get the RecordWriter for the given job.

Specified by:

getRecordWriter in interface OutputFormat<K,V>

Overrides:

getRecordWriter in class FilterOutputFormat<K,V>

job - configuration for the job whose output is being written.

name - the unique name for this part of the output.

progress - mechanism for reporting progress while writing to file.

Returns:

a RecordWriter to write the output for the job.

Throws:

IOException

checkOutputSpecs

public void checkOutputSpecs(FileSystem ignored,
                             JobConf job)
                      throws IOException

Description copied from interface: OutputFormat

Check for validity of the output-specification for the job.

This is to validate the output specification for the job when it is a job is submitted. Typically checks that it does not already exist, throwing an exception when it already exists, so that output is not overwritten.

Implementations which write to filesystems which support delegation tokens usually collect the tokens for the destination path(s) and attach them to the job configuration.

Specified by:

checkOutputSpecs in interface OutputFormat<K,V>

Overrides:

checkOutputSpecs in class FilterOutputFormat<K,V>

job - job configuration.

Throws:

IOException - when output should not be attempted