See: Description
Interface | Description |
---|---|
Collator<ValueIn,ValueOut> |
This interface can be implemented to define a Collator which is executed after calculation
of the MapReduce algorithm on remote cluster nodes but before returning the final result.
Collator can, for example, be used to sum up a final value. |
CombinerFactory<KeyIn,ValueIn,ValueOut> | |
Context<K,V> |
The Context interface is used for emitting keys and values to the intermediate working space of
the MapReduce algorithm.
|
Job<KeyIn,ValueIn> |
This interface describes a mapreduce Job that is build by
JobTracker.newJob(KeyValueSource) .It is used to execute mappings and calculations on the different cluster nodes and reduce or collate these mapped values to results. |
JobCompletableFuture<V> |
This is a special version of ICompletableFuture to return the assigned job
id of the submit operation.
|
JobPartitionState |
An implementation of this interface contains current information about
the status of an process piece while operation is executing.
|
JobProcessInformation |
This interface holds basic information about a running map reduce job, such as the
state of the different partitions and the number of currently processed
records.
The number of processed records is not a real time value, it is updated on a regular basis (after 1000 processed elements per node). |
JobTracker |
The JobTracker interface is used to create instances of
Job s depending
on the given data structure / data source. |
KeyPredicate<Key> |
This interface is used to pre-evaluate keys before spreading the MapReduce task to the cluster.
|
LifecycleMapper<KeyIn,ValueIn,KeyOut,ValueOut> |
The LifecycleMapper interface is a more sophisticated version of
Mapper normally used for more complex
algorithms with a need for initialization and finalization. |
Mapper<KeyIn,ValueIn,KeyOut,ValueOut> |
The interface Mapper is used to build mappers for the
Job . |
MappingJob<EntryKey,KeyIn,ValueIn> |
This interface describes a mapping mapreduce Job.
For further information see Job . |
PartitionIdAware |
This interface can be used to mark implementation being aware of the data partition
it is currently working on.
|
ReducerFactory<KeyIn,ValueIn,ValueOut> |
A ReducerFactory implementation is used to build
Reducer instances per key.An implementation needs to be serializable by Hazelcast since it might be distributed inside the cluster to do parallel calculations for reducing. |
ReducingJob<EntryKey,KeyIn,ValueIn> |
This interface describes a reducing mapreduce Job.
For further information Job . |
ReducingSubmittableJob<EntryKey,KeyIn,ValueIn> |
This interface describes a submittable mapreduce Job.
For further information Job . |
TrackableJob<V> |
This interface describes a trackable job.
|
Class | Description |
---|---|
Combiner<ValueIn,ValueOut> | |
KeyValueSource<K,V> | |
LifecycleMapperAdapter<KeyIn,ValueIn,KeyOut,ValueOut> |
The abstract LifecycleMapperAdapter superclass is used to ease building mappers for the
Job . |
Reducer<ValueIn,ValueOut> |
The abstract Reducer class is used to build reducers for the
Job .Reducers may be distributed inside of the cluster but there is always only one Reducer per key. |
Enum | Description |
---|---|
JobPartitionState.State |
Definition of the processing states
|
TopologyChangedStrategy |
This enum class is used to define how a map reduce job behaves
if the job owner recognizes a topology changed event.
When members are leaving the cluster, it might lose processed data chunks that were already send to the reducers on the leaving node. Also, on any topology change, there is a redistribution of the member assigned partitions, which means that a map job might have a problem finishing its currently processed partition. The default behavior is to immediately cancel the running task and throw an TopologyChangedException , but it is possible
to submit the same job configuration again if
JobTracker.getTrackableJob(String)
returns null for the requested job id. |
Exception | Description |
---|---|
RemoteMapReduceException |
This exception class is used to show stack traces of multiple failed
remote operations at once.
|
TopologyChangedException |
This exception is thrown when a topology change happens during the
execution of a map reduce job and the
TopologyChangedStrategy
is set to TopologyChangedStrategy.CANCEL_RUNNING_OPERATION . |
This package contains the MapReduce API definition for Hazelcast.
All map reduce operations running in a distributed manner inside the
active Hazelcast cluster. Therefor Mapper
,
Combiner
and Reducer
implementations need to be fully serializable by Hazelcast. Any of the
existing serialization patterns are available for those classes, too.
If custom KeyValueSource
is provided above
statement also applies to this implementation.
For a basic idea how to use this framework see Job
or Mapper
, Combiner
or
Reducer
.
Copyright © 2016 Hazelcast, Inc.. All Rights Reserved.