Package org.apache.storm.windowing

# Interface TriggerPolicy<T,S>

Type Parameters:
  `T` - the type of the event that is tracked

All Known Implementing Classes:
  `CountTriggerPolicy`, `TimeTriggerPolicy`, `WatermarkCountTriggerPolicy`, `WatermarkTimeTriggerPolicy`

public interface TriggerPolicy<T,S>
Triggers the window calculations based on the policy.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `S`
  `getState()`
  Return runtime state to be checkpointed by the framework for restoring the trigger policy in case of failures.
  `void`
  `reset()`
  resets the trigger policy.
  `void`
  `restoreState(S state)`
  Restore the trigger policy from the state that was earlier checkpointed by the framework.
  `void`
  `shutdown()`
  Any clean up could be handled here.
  `void`
  `start()`
  Starts the trigger policy.
  `void`
  `track(Event<T> event)`
  Tracks the event and could use this to invoke the trigger.

- ## Method Details

  - ### track

    void track(Event<T> event)
    Tracks the event and could use this to invoke the trigger.
    Parameters:
      `event` - the input event

  - ### reset

    void reset()
    resets the trigger policy.

  - ### start

    void start()
    Starts the trigger policy. This can be used during recovery to start the triggers after recovery is complete.

  - ### shutdown

    void shutdown()
    Any clean up could be handled here.

  - ### getState

    S getState()
    Return runtime state to be checkpointed by the framework for restoring the trigger policy in case of failures.
    Returns:
      the state

  - ### restoreState

    void restoreState(S state)
    Restore the trigger policy from the state that was earlier checkpointed by the framework.
    Parameters:
      `state` - the state