TriggerPolicy (Storm 2.7.1 API)

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

All Methods Instance Methods Abstract Methods
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 Detail
  - 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