package com.lambdaworks.redis.resource;
import java.util.concurrent.TimeUnit;
/**
* Delay that increases using equal jitter strategy.
*
* <p>
* Considering retry attempts start at 1, attempt 0 would be the initial call and will always yield 0 (or the lower). Then, each
* retry step will by default yield {@code randomBetween(0, base * 2 ^ (attempt - 1))}.
*
* This strategy is based on <a href="https://www.awsarchitectureblog.com/2015/03/backoff.html">Exponential Backoff and
* Jitter</a>.
* </p>
*
* @author Jongyeol Choi
* @since 4.2
*/
class EqualJitterDelay extends ExponentialDelay {
private final long base;
EqualJitterDelay(long lower, long upper, long base, TimeUnit unit) {
super(lower, upper, unit, 2);
this.base = base;
}
@Override
public long createDelay(long attempt) {
long value = randomBetween(0, base * calculatePowerOfTwo(attempt));
return applyBounds(value);
}
}