@InterfaceAudience.Private @InterfaceStability.Unstable public class DelegatingMapper<K1,V1,K2,V2> extends Object implements Mapper<K1,V1,K2,V2>
Mapper that delegates behaviour of paths to multiple other
mappers.| Constructor and Description |
|---|
DelegatingMapper() |
| Modifier and Type | Method and Description |
|---|---|
void |
close() |
void |
configure(JobConf conf)
Initializes a new instance from a
JobConf. |
void |
map(K1 key,
V1 value,
OutputCollector<K2,V2> outputCollector,
Reporter reporter)
Maps a single input key/value pair into an intermediate key/value pair.
|
public void map(K1 key, V1 value, OutputCollector<K2,V2> outputCollector, Reporter reporter) throws IOException
MapperOutput pairs need not be of the same types as input pairs. A given
input pair may map to zero or many output pairs. Output pairs are
collected with calls to
OutputCollector.collect(Object,Object).
Applications can use the Reporter provided to report progress
or just indicate that they are alive. In scenarios where the application
takes significant amount of time to process individual key/value
pairs, this is crucial since the framework might assume that the task has
timed-out and kill that task. The other way of avoiding this is to set
mapreduce.task.timeout to a high-enough value (or even zero for no
time-outs).
public void configure(JobConf conf)
JobConfigurableJobConf.configure in interface JobConfigurableconf - the configurationpublic void close()
throws IOException
close in interface Closeableclose in interface AutoCloseableIOExceptionCopyright © 2008–2022 Apache Software Foundation. All rights reserved.