MapReduce.MapEmitter<K,V>, MapReduce.NullObject, MapReduce.ReduceEmitter<OK,OV>, MapReduce.Stage| Modifier and Type | Field and Description | 
|---|---|
| static String | GROUP_BY_STEP_STEP_ID | 
MAP_REDUCE| Constructor and Description | 
|---|
| GroupMapReduce(GroupStep<S,K,V> step) | 
| Modifier and Type | Method and Description | 
|---|---|
| GroupStep.GroupMapReduce<S,K,V> | clone()When multiple workers on a single machine need MapReduce instances, it is possible to use clone. | 
| boolean | doStage(MapReduce.Stage stage)A MapReduce job can be map-only, map-reduce-only, or map-combine-reduce. | 
| Map<K,V> | generateFinalResult(Iterator<KeyValue<K,V>> keyValues)The key/value pairs emitted by reduce() (or map() in a map-only job) can be iterated to generate a local JVM Java object. | 
| String | getMemoryKey()The results of the MapReduce job are associated with a memory-key to ultimately be stored in  Memory. | 
| void | loadState(Graph graph,
         Configuration configuration)When it is necessary to load the state of a MapReduce job, this method is called. | 
| void | map(Vertex vertex,
   MapReduce.MapEmitter<K,Collection<?>> emitter)The map() method is logically executed at all vertices in the graph in parallel. | 
| void | reduce(K key,
      Iterator<Collection<?>> values,
      MapReduce.ReduceEmitter<K,V> emitter)The reduce() method is logically on the "machine" the respective key hashes to. | 
| void | storeState(Configuration configuration)When it is necessary to store the state of a MapReduce job, this method is called. | 
| String | toString() | 
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitaddResultToMemory, combine, createMapReduce, getMapKeySort, getReduceKeySort, workerEnd, workerStartpublic static final String GROUP_BY_STEP_STEP_ID
public void storeState(Configuration configuration)
MapReducestoreState in interface MapReduce<K,Collection<?>,K,V,Map<K,V>>configuration - the configuration to store the state of the MapReduce job in.public void loadState(Graph graph, Configuration configuration)
MapReducepublic boolean doStage(MapReduce.Stage stage)
MapReducepublic void map(Vertex vertex, MapReduce.MapEmitter<K,Collection<?>> emitter)
MapReducepublic void reduce(K key, Iterator<Collection<?>> values, MapReduce.ReduceEmitter<K,V> emitter)
MapReducepublic Map<K,V> generateFinalResult(Iterator<KeyValue<K,V>> keyValues)
MapReducegenerateFinalResult in interface MapReduce<K,Collection<?>,K,V,Map<K,V>>keyValues - the key/value pairs that were emitted from reduce() (or map() in a map-only job)public String getMemoryKey()
MapReduceMemory.getMemoryKey in interface MapReduce<K,Collection<?>,K,V,Map<K,V>>public GroupStep.GroupMapReduce<S,K,V> clone()
MapReduceMapReduce.storeState(Configuration) and MapReduce.loadState(org.apache.tinkerpop.gremlin.structure.Graph, Configuration) model.
 The default implementation simply returns the object as it assumes that the MapReduce instance is a stateless singleton.Copyright © 2013–2015 Apache Software Foundation. All rights reserved.