public interface OutputFormat<K,V>
OutputFormat
describes the output-specification for a
Map-Reduce job.
The Map-Reduce framework relies on the OutputFormat
of the
job to:
RecordWriter
implementation to be used to write out
the output files of the job. Output files are stored in a
FileSystem
.
RecordWriter
,
JobConf
限定符和类型 | 方法和说明 |
---|---|
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. |
RecordWriter<K,V> getRecordWriter(FileSystem ignored, JobConf job, String name, Progressable progress) throws IOException
RecordWriter
for the given job.ignored
- 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.RecordWriter
to write the output for the job.IOException
void checkOutputSpecs(FileSystem ignored, JobConf job) throws IOException
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.
ignored
- job
- job configuration.IOException
- when output should not be attemptedCopyright © 2009 The Apache Software Foundation