package com.ctrip.apollo.core.schedule;

 /**

  * @author Jason Song(song_s@ctrip.com)

  */

 public class ExponentialSchedulePolicy implements SchedulePolicy {

   private final long delayTimeLowerBound;

   private final long delayTimeUpperBound;

   private long lastDelayTime;

   public ExponentialSchedulePolicy(long delayTimeLowerBound, long delayTimeUpperBound) {

     this.delayTimeLowerBound = delayTimeLowerBound;

     this.delayTimeUpperBound = delayTimeUpperBound;

   }

   @Override

   public long fail() {

     long delayTime = lastDelayTime;

     if (delayTime == 0) {

       delayTime = delayTimeLowerBound;

     } else {

       delayTime = Math.min(lastDelayTime << 1, delayTimeUpperBound);

     }

     lastDelayTime = delayTime;

     return delayTime;

   }

   @Override

   public void success() {

     lastDelayTime = 0;

   }

 }