Class AbstractRankerBolt

All Implemented Interfaces:
Serializable, IBasicBolt, IComponent
Direct Known Subclasses:
IntermediateRankingsBolt, TotalRankingsBolt

public abstract class AbstractRankerBolt extends BaseBasicBolt
This abstract bolt provides the basic behavior of bolts that rank objects according to their count.

It uses a template method design pattern for execute(Tuple, BasicOutputCollector) to allow actual bolt implementations to specify how incoming tuples are processed, i.e. how the objects embedded within those tuples are retrieved and counted.

See Also:
  • Constructor Details

    • AbstractRankerBolt

      public AbstractRankerBolt()
    • AbstractRankerBolt

      public AbstractRankerBolt(int topN)
    • AbstractRankerBolt

      public AbstractRankerBolt(int topN, int emitFrequencyInSeconds)
  • Method Details

    • getRankings

      protected Rankings getRankings()
    • execute

      public final void execute(Tuple tuple, BasicOutputCollector collector)
      This method functions as a template method (design pattern).
    • declareOutputFields

      public void declareOutputFields(OutputFieldsDeclarer declarer)
      Description copied from interface: IComponent
      Declare the output schema for all the streams of this topology.
      declarer - this is used to declare output stream ids, output fields, and whether or not each output stream is a direct stream
    • getComponentConfiguration

      public Map<String,Object> getComponentConfiguration()
      Description copied from interface: IComponent
      Declare configuration specific to this component. Only a subset of the "topology.*" configs can be overridden. The component configuration can be further overridden when constructing the topology using TopologyBuilder
      Specified by:
      getComponentConfiguration in interface IComponent
      getComponentConfiguration in class BaseComponent