LeaderRetrievalService (Flink : 2.0-SNAPSHOT API)

All Known Implementing Classes:

DefaultLeaderRetrievalService, StandaloneLeaderRetrievalService
```
public interface LeaderRetrievalService
```
This interface has to be implemented by a service which retrieves the current leader and notifies a listener about it.
Prior to using this service it has to be started by calling the start method. The start method also takes the LeaderRetrievalListener as an argument. The service can only be started once.
The service should be stopped by calling the stop method.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`start(LeaderRetrievalListener listener)`	Starts the leader retrieval service with the given listener to listen for new leaders.
`void`	`stop()`	Stops the leader retrieval service.

- Method Detail
  - start
```
void start(LeaderRetrievalListener listener)
    throws Exception
```
    Starts the leader retrieval service with the given listener to listen for new leaders. This method can only be called once.
    
    Parameters:
    
    listener - The leader retrieval listener which will be notified about new leaders.
    
    Throws:
    
    Exception
  - stop
```
void stop()
   throws Exception
```
    Stops the leader retrieval service.
    
    Throws:
    
    Exception