Package org.apache.tinkerpop.gremlin.process.computer.ranking.pagerank

Class PageRankMapReduce

java.lang.Object
org.apache.tinkerpop.gremlin.process.computer.util.StaticMapReduce<Object,Double,Object,Double,Iterator<KeyValue<Object,Double>>>
org.apache.tinkerpop.gremlin.process.computer.ranking.pagerank.PageRankMapReduce
All Implemented Interfaces:
Cloneable, MapReduce<Object,Double,Object,Double,Iterator<KeyValue<Object,Double>>>
public class PageRankMapReduce extends StaticMapReduce<Object,Double,Object,Double,Iterator<KeyValue<Object,Double>>>
Author:
Marko A. Rodriguez (http://markorodriguez.com)

  • Field Details

  • Method Details

    • storeState

      public void storeState(org.apache.commons.configuration2.Configuration configuration)
      Description copied from interface: MapReduce
      When it is necessary to store the state of a MapReduce job, this method is called. This is typically required when the MapReduce job needs to be serialized to another machine. Note that what is stored is simply the instance state, not any processed data.
      Specified by:
      storeState in interface MapReduce<Object,Double,Object,Double,Iterator<KeyValue<Object,Double>>>
      Overrides:
      storeState in class StaticMapReduce<Object,Double,Object,Double,Iterator<KeyValue<Object,Double>>>
      Parameters:
      configuration - the configuration to store the state of the MapReduce job in.

    • loadState

      public void loadState(Graph graph, org.apache.commons.configuration2.Configuration configuration)
      Description copied from interface: MapReduce
      When it is necessary to load the state of a MapReduce job, this method is called. This is typically required when the MapReduce job needs to be serialized to another machine. Note that what is loaded is simply the instance state, not any processed data.

      It is important that the state loaded from loadState() is identical to any state created from a constructor. For those GraphComputers that do not need to use Configurations to migrate state between JVMs, the constructor will only be used.

      Parameters:
      graph - the graph the MapReduce job will run against
      configuration - the configuration to load the state of the MapReduce job from.

    • doStage

      public boolean doStage(MapReduce.Stage stage)
      Description copied from interface: MapReduce
      A MapReduce job can be map-only, map-reduce-only, or map-combine-reduce. Before executing the particular stage, this method is called to determine if the respective stage is defined. This method should return true if the respective stage as a non-default method implementation.
      Parameters:
      stage - the stage to check for definition.
      Returns:
      whether that stage should be executed.

    • map

      public void map(Vertex vertex, MapReduce.MapEmitter<Object,Double> emitter)
      Description copied from interface: MapReduce
      The map() method is logically executed at all vertices in the graph in parallel. The map() method emits key/value pairs given some analysis of the data in the vertices (and/or its incident edges). All MapReduce classes must at least provide an implementation of MapReduce#map(Vertex, MapEmitter).
      Parameters:
      vertex - the current vertex being map() processed.
      emitter - the component that allows for key/value pairs to be emitted to the next stage.

    • generateFinalResult

      public Iterator<KeyValue<Object,Double>> generateFinalResult(Iterator<KeyValue<Object,Double>> keyValues)
      Description copied from interface: MapReduce
      The key/value pairs emitted by reduce() (or map() in a map-only job) can be iterated to generate a local JVM Java object.
      Parameters:
      keyValues - the key/value pairs that were emitted from reduce() (or map() in a map-only job)
      Returns:
      the resultant object formed from the emitted key/values.

    • getMemoryKey

      public String getMemoryKey()
      Description copied from interface: MapReduce
      The results of the MapReduce job are associated with a memory-key to ultimately be stored in Memory.
      Returns:
      the memory key of the generated result object.

    • toString

      public String toString()
      Overrides:
      toString in class StaticMapReduce<Object,Double,Object,Double,Iterator<KeyValue<Object,Double>>>

    • build

      public static PageRankMapReduce.Builder build()