# Package org.apache.storm.windowing

package org.apache.storm.windowing

- Related Packages
  Package
  Description
  org.apache.storm
  org.apache.storm.windowing.persistence
- Class
  Description
  CountEvictionPolicy<T>
  An eviction policy that tracks event counts and can evict based on a threshold count.
  CountTriggerPolicy<T>
  A trigger that tracks event counts and calls back `TriggerHandler.onTrigger()` when the count threshold is hit.
  DefaultEvictionContext
  Event<T>
  An event is a wrapper object that gets stored in the window.
  EventImpl<T>
  EvictionContext
  Context information that can be used by the eviction policy.
  EvictionPolicy<T,S>
  Eviction policy tracks events and decides whether an event should be evicted from the window or not.
  EvictionPolicy.Action
  The action to be taken when `EvictionPolicy.evict(Event)` is invoked.
  StatefulWindowManager<T>
  Window manager that handles windows with state persistence.
  TimeEvictionPolicy<T>
  Eviction policy that evicts events based on time duration.
  TimestampExtractor
  Interface to be implemented for extracting timestamp from a tuple.
  TimeTriggerPolicy<T>
  Invokes `TriggerHandler.onTrigger()` after the duration.
  TriggerHandler
  The callback fired by `TriggerPolicy` when the trigger condition is satisfied.
  TriggerPolicy<T,S>
  Triggers the window calculations based on the policy.
  TupleWindow
  A `Window` that contains `Tuple` objects.
  TupleWindowImpl
  Holds the expired, new and current tuples in a window.
  TupleWindowIterImpl
  An iterator based implementation over the events in a window.
  WatermarkCountEvictionPolicy<T>
  An eviction policy that tracks count based on watermark ts and evicts events up to the watermark based on a threshold count.
  WatermarkCountTriggerPolicy<T>
  A trigger policy that tracks event counts and sets the context for eviction policy to evict based on latest watermark time.
  WaterMarkEvent<T>
  Watermark event used for tracking progress of time when processing event based ts.
  WaterMarkEventGenerator<T>
  Tracks tuples across input streams and periodically emits watermark events.
  WatermarkTimeEvictionPolicy<T>
  An eviction policy that evicts events based on time duration taking watermark time and event lag into account.
  WatermarkTimeTriggerPolicy<T>
  Handles watermark events and triggers `TriggerHandler.onTrigger()` for each window interval that has events to be processed up to the watermark ts.
  Window<T>
  A view of events in a sliding window.
  WindowLifecycleListener<T>
  A callback for expiry, activation of events tracked by the `WindowManager`.
  WindowManager<T>
  Tracks a window of events and fires `WindowLifecycleListener` callbacks on expiry of events or activation of the window due to `TriggerPolicy`.