接口 BackOff

public interface BackOff

Provide a BackOffExecution that indicates the rate at which an operation should be retried.

Users of this interface are expected to use it like this:

 BackOffExecution exec = backOff.start();

 // In the operation recovery/retry loop:
 long waitInterval = exec.nextBackOff();
 if (waitInterval == BackOffExecution.STOP) {
     // do not retry operation
 }
 else {
     // sleep, e.g. Thread.sleep(waitInterval)
     // retry operation
 }
 }

Once the underlying operation has completed successfully, the execution instance can be simply discarded.