- Direct Known Subclasses:
public abstract class ReducerSelector
- extends Object
This class and its specific implementation are used to group the outputs of
the Map task to the Reduce task queues. In a typical MapReduce computation,
all Map tasks can produce some result that maps to a particular Reduce task.
So normally all the Map tasks have some output to go into all the Reduce
tasks. This behavior can be change by extending this abstract class.
|Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
protected String jobId
protected int numReducers
protected String sinkBase
protected ReducerSelector(int numReducers,
public void configure(JobConf jobConf,
public String getJobId()
public int getNumReducers()
public abstract int getReducerNumber(Key key)
- Returns the reducer number for a given Key. This mapping can be anything
from Hashing to specific configuration such as one to one.
- reducer number for this key.
public String getSinkBase()
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