Package org.apache.storm.topology

# Interface IStatefulWindowedBolt<T extends State>

All Superinterfaces:
  `IComponent`, `IStatefulComponent<T>`, `IWindowedBolt`, `Serializable`

All Known Implementing Classes:
  `BaseStatefulWindowedBolt`

public interface IStatefulWindowedBolt<T extends State> extends IStatefulComponent<T>, IWindowedBolt
A windowed bolt abstraction for supporting windowing operation with state.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `default boolean`
  `isPersistent()`
  If the stateful windowed bolt should have its windows persisted in state and maintain a subset of events in memory.
  `default long`
  `maxEventsInMemory()`
  The maximum number of window events to keep in memory.

  ### Methods inherited from interface org.apache.storm.topology.IComponent

  `declareOutputFields, getComponentConfiguration`

  ### Methods inherited from interface org.apache.storm.topology.IStatefulComponent

  `initState, preCommit, prePrepare, preRollback`

  ### Methods inherited from interface org.apache.storm.topology.IWindowedBolt

  `cleanup, execute, getTimestampExtractor, prepare`

- ## Method Details

  - ### isPersistent

    default boolean isPersistent()
    If the stateful windowed bolt should have its windows persisted in state and maintain a subset of events in memory.

    The default is to keep all the window events in memory.

    Returns:
      true if the windows should be persisted

  - ### maxEventsInMemory

    default long maxEventsInMemory()
    The maximum number of window events to keep in memory.