# Uses of Interface
org.apache.storm.streams.operations.Reducer

Packages that use Reducer
Package
Description
org.apache.storm.streams
org.apache.storm.streams.processors

- ## Uses of Reducer in org.apache.storm.streams

  Methods in org.apache.storm.streams with parameters of type Reducer
  Modifier and Type
  Method
  Description
  `Stream<T>`
  Stream.`reduce(Reducer<T> reducer)`
  Performs a reduction on the elements of this stream, by repeatedly applying the reducer.
  `PairStream<K,V>`
  PairStream.`reduceByKey(Reducer<V> reducer)`
  Performs a reduction on the values for each key of this stream by repeatedly applying the reducer.
  `PairStream<K,V>`
  PairStream.`reduceByKeyAndWindow(Reducer<V> reducer, Window<?,?> window)`
  Returns a new stream where the values that arrive within a window having the same key will be reduced by repeatedly applying the reducer.

- ## Uses of Reducer in org.apache.storm.streams.processors

  Constructors in org.apache.storm.streams.processors with parameters of type Reducer
  Modifier
  Constructor
  Description
  ``
  `ReduceByKeyProcessor(Reducer<V> reducer)`
  ``
  `ReduceProcessor(Reducer<T> reducer)`