TimerService (Flink : 2.0-SNAPSHOT API)

All Superinterfaces:

ProcessingTimeService, ProcessingTimeService

All Known Implementing Classes:

NeverFireProcessingTimeService, SystemProcessingTimeService
```
@Internal
public interface TimerService
extends ProcessingTimeService
```
A common timer service interface with life cycle methods.
The registration of timers follows a life cycle of three phases:
1. In the initial state, it accepts timer registrations and triggers when the time is reached.
2. After calling ProcessingTimeService.quiesce(), further calls to ProcessingTimeService.registerTimer(long, ProcessingTimeCallback) will not register any further timers, and will return a "dummy" future as a result. This is used for clean shutdown, where currently firing timers are waited for and no future timers can be scheduled, without causing hard exceptions.
3. After a call to shutdownService(), all calls to ProcessingTimeService.registerTimer(long, ProcessingTimeCallback) will result in a hard exception.

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.flink.api.common.operators.ProcessingTimeService
  ProcessingTimeService.ProcessingTimeCallback

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`isTerminated()`	Returns `true` if the service has been shut down, `false` otherwise.
`void`	`shutdownService()`	Shuts down and clean up the timer service provider hard and immediately.
`boolean`	`shutdownServiceUninterruptible(long timeoutMs)`	Shuts down and clean up the timer service provider hard and immediately.

Methods inherited from interface org.apache.flink.api.common.operators.ProcessingTimeService
registerTimer

Methods inherited from interface org.apache.flink.streaming.runtime.tasks.ProcessingTimeService
getClock, getCurrentProcessingTime, quiesce, scheduleAtFixedRate, scheduleWithFixedDelay

- Method Detail
  - isTerminated
```
boolean isTerminated()
```
    Returns true if the service has been shut down, false otherwise.
  - shutdownService
```
void shutdownService()
```
    Shuts down and clean up the timer service provider hard and immediately. This does not wait for any timer to complete. Any further call to ProcessingTimeService.registerTimer(long, ProcessingTimeCallback) will result in a hard exception.
  - shutdownServiceUninterruptible
```
boolean shutdownServiceUninterruptible(long timeoutMs)
```
    Shuts down and clean up the timer service provider hard and immediately. This does not wait for any timer to complete. Any further call to ProcessingTimeService.registerTimer(long, ProcessingTimeCallback) will result in a hard exception. This call cannot be interrupted and will block until the shutdown is completed or the timeout is exceeded.
    
    Parameters:
    
    timeoutMs - timeout for blocking on the service shutdown in milliseconds.
    
    Returns:
    
    returns true iff the shutdown was completed.