org.apache.hadoop.mapred.lib.db
Class DBOutputFormat<K extends DBWritable,V>

java.lang.Object
  extended by org.apache.hadoop.mapreduce.OutputFormat<K,V>
      extended by org.apache.hadoop.mapreduce.lib.db.DBOutputFormat<K,V>
          extended by org.apache.hadoop.mapred.lib.db.DBOutputFormat<K,V>
All Implemented Interfaces:
OutputFormat<K,V>

@InterfaceAudience.Public
@InterfaceStability.Stable
public class DBOutputFormat<K extends DBWritable,V>
extends DBOutputFormat<K,V>
implements OutputFormat<K,V>


Constructor Summary
DBOutputFormat()
           
 
Method Summary
 void checkOutputSpecs(FileSystem filesystem, JobConf job)
          Check for validity of the output-specification for the job.
 RecordWriter<K,V> getRecordWriter(FileSystem filesystem, JobConf job, String name, Progressable progress)
          Get the RecordWriter for the given job.
static void setOutput(JobConf job, String tableName, int fieldCount)
          Initializes the reduce-part of the job with the appropriate output settings
static void setOutput(JobConf job, String tableName, String... fieldNames)
          Initializes the reduce-part of the job with the appropriate output settings
 
Methods inherited from class org.apache.hadoop.mapreduce.lib.db.DBOutputFormat
checkOutputSpecs, constructQuery, getOutputCommitter, getRecordWriter, setOutput, setOutput
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DBOutputFormat

public DBOutputFormat()
Method Detail

checkOutputSpecs

public void checkOutputSpecs(FileSystem filesystem,
                             JobConf job)
                      throws IOException
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.

Specified by:
checkOutputSpecs in interface OutputFormat<K extends DBWritable,V>
job - job configuration.
Throws:
IOException - when output should not be attempted

getRecordWriter

public RecordWriter<K,V> getRecordWriter(FileSystem filesystem,
                                         JobConf job,
                                         String name,
                                         Progressable progress)
                                                     throws IOException
Get the RecordWriter for the given job.

Specified by:
getRecordWriter in interface OutputFormat<K extends DBWritable,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

setOutput

public static void setOutput(JobConf job,
                             String tableName,
                             String... fieldNames)
Initializes the reduce-part of the job with the appropriate output settings

Parameters:
job - The job
tableName - The table to insert data into
fieldNames - The field names in the table.

setOutput

public static void setOutput(JobConf job,
                             String tableName,
                             int fieldCount)
Initializes the reduce-part of the job with the appropriate output settings

Parameters:
job - The job
tableName - The table to insert data into
fieldCount - the number of fields in the table.


Copyright © 2012 Apache Software Foundation. All Rights Reserved.