org.infinispan.distexec.mapreduce

Interface MapReduceManager

All Known Implementing Classes:

MapReduceManagerImpl

public interface MapReduceManager

MapReduceManager is an internal Infinispan component receiving map/reduce invocations arriving from remote Infinispan nodes.

This interface should never be implemented by clients.

Since:

5.2

Author:

Vladimir Blagojevic

Method Summary

Modifier and Type	Method and Description
ExecutorService	getExecutorService() ExecutorService provided for local task execution
<KIn,VIn,KOut,VOut> Set<KOut>	mapAndCombineForDistributedReduction(MapCombineCommand<KIn,VIn,KOut,VOut> mcc) Invoked when MapCombineCommand arrives to a target Infinispan node and returns set of intermediate keys that needs to be reduced.
<KIn,VIn,KOut,VOut> Map<KOut,List<VOut>>	mapAndCombineForLocalReduction(MapCombineCommand<KIn,VIn,KOut,VOut> mcc) Invoked when MapCombineCommand arrives to a target Infinispan node and returns map of resulting values that need to be reduced.
<T> Map<Address,List<T>>	mapKeysToNodes(DistributionManager dm, String taskId, Collection<T> keysToMap) Maps Map/Reduce task intermediate or input keys to nodes on Infinispan cluster
<KOut,VOut> Map<KOut,VOut>	reduce(ReduceCommand<KOut,VOut> reducer) Invoked when ReduceCommand arrives to a target Infinispan node.
<KOut,VOut> void	reduce(ReduceCommand<KOut,VOut> reducer, String resultCache) Invoked when ReduceCommand arrives to a target Infinispan node.

Method Detail

mapAndCombineForDistributedReduction

<KIn,VIn,KOut,VOut> Set<KOut> mapAndCombineForDistributedReduction(MapCombineCommand<KIn,VIn,KOut,VOut> mcc)
                                                            throws InterruptedException

Invoked when MapCombineCommand arrives to a target Infinispan node and returns set of intermediate keys that needs to be reduced.

Parameters:

mcc - MapCombineCommand sent from MapReduceTask

Returns:

a set of intermediate keys to be reduced distributively

Throws:

InterruptedException

mapAndCombineForLocalReduction

<KIn,VIn,KOut,VOut> Map<KOut,List<VOut>> mapAndCombineForLocalReduction(MapCombineCommand<KIn,VIn,KOut,VOut> mcc)
                                                                 throws InterruptedException

Invoked when MapCombineCommand arrives to a target Infinispan node and returns map of resulting values that need to be reduced.

Unlike mapAndCombineForDistributedReduction(MapCombineCommand) implementations should return a map Map> which should be ready for reduction at master Infinispan node

Parameters:

mcc - MapCombineCommand sent from MapReduceTask

Returns:

a map Map> which should be ready for reduction at master Infinispan node

Throws:

InterruptedException

reduce

<KOut,VOut> Map<KOut,VOut> reduce(ReduceCommand<KOut,VOut> reducer)
                           throws InterruptedException

Invoked when ReduceCommand arrives to a target Infinispan node. Implementations should return a map of reduced output keys and values to be returned to invoker of MapReduceTask

Parameters:

reducer - ReduceCommand sent from MapReduceTask

Returns:

map of reduced output keys and values returned to MapReduceTask

Throws:

InterruptedException

reduce

<KOut,VOut> void reduce(ReduceCommand<KOut,VOut> reducer,
                        String resultCache)
                 throws InterruptedException

Invoked when ReduceCommand arrives to a target Infinispan node. However, instead of returning a resulting Map to master node, reduce command emits results of reduce phase to a specified resulting cache.

Parameters:

reducer - ReduceCommand sent from MapReduceTask

resultCache - result cache to store results of reduce phase

Throws:

InterruptedException

mapKeysToNodes

<T> Map<Address,List<T>> mapKeysToNodes(DistributionManager dm,
                                        String taskId,
                                        Collection<T> keysToMap)

Maps Map/Reduce task intermediate or input keys to nodes on Infinispan cluster

Parameters:

dm - distribution manager to use for locating keys on hash wheel

taskId - id of the map/reduce task

keysToMap - list of input keys to locate in the cluster

Returns:

map where each key is an Address in the cluster and value are the keys mapped to that Address

getExecutorService

ExecutorService getExecutorService()

ExecutorService provided for local task execution

Returns:

ExecutorService for local tasks