Package | Description |
---|---|
org.apache.hadoop.mapred | |
org.apache.hadoop.mapred.lib | |
org.apache.hadoop.mapred.lib.aggregate |
Modifier and Type | Interface and Description |
---|---|
interface |
Mapper<K1,V1,K2,V2>
Maps input key/value pairs to a set of intermediate key/value pairs.
|
interface |
Reducer<K2,V2,K3,V3>
Reduces a set of intermediate values which share a key to a smaller set of
values.
|
Modifier and Type | Class and Description |
---|---|
class |
ChainMapper
The ChainMapper class allows to use multiple Mapper classes within a single
Map task.
|
class |
ChainReducer
The ChainReducer class allows to chain multiple Mapper classes after a
Reducer within the Reducer task.
|
class |
FieldSelectionMapReduce<K,V>
This class implements a mapper/reducer class that can be used to perform
field selections in a manner similar to unix cut.
|
class |
IdentityMapper<K,V>
Implements the identity function, mapping inputs directly to outputs.
|
class |
IdentityReducer<K,V>
Performs no reduction, writing all input values directly to the output.
|
class |
InverseMapper<K,V>
A
Mapper that swaps keys and values. |
class |
LongSumReducer<K>
A
Reducer that sums long values. |
class |
RegexMapper<K>
A
Mapper that extracts text matching a regular expression. |
class |
TokenCountMapper<K>
A
Mapper that maps text values into <token,freq> pairs. |
Modifier and Type | Class and Description |
---|---|
class |
ValueAggregatorCombiner<K1 extends WritableComparable,V1 extends Writable>
This class implements the generic combiner of Aggregate.
|
class |
ValueAggregatorJobBase<K1 extends WritableComparable,V1 extends Writable>
This abstract class implements some common functionalities of the
the generic mapper, reducer and combiner classes of Aggregate.
|
class |
ValueAggregatorMapper<K1 extends WritableComparable,V1 extends Writable>
This class implements the generic mapper of Aggregate.
|
class |
ValueAggregatorReducer<K1 extends WritableComparable,V1 extends Writable>
This class implements the generic reducer of Aggregate.
|
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