com.couchbase.client.core.time

## Class ExponentialDelay

• ```public class ExponentialDelay
extends Delay```

Delay which increases exponentially on every attempt.

Considering retry attempts start at 1, attempt 0 would be the initial call and will always yield 0 (or the lower bound). Then each retry step will by default yield `1 * 2 ^ (attemptNumber-1)`. Actually each step can be based on a different number than 1 unit of time using the `growBy` parameter: `growBy * 2 ^ (attemptNumber-1)`.

By default with growBy = 1 this gives us 0 (initial attempt), 1, 2, 4, 8, 16, 32…

Each of the resulting values that is below the `lowerBound` will be replaced by the lower bound, and each value over the `upperBound` will be replaced by the upper bound.

For example, given the following `Delay.exponential(TimeUnit.MILLISECONDS, 4000, 0, 500)`

• the upper of 4000 means the delay will be capped at 4s
• the lower of 0 is useful to allow for immediate execution of original attempt, attempt 0 (if we ever call the delay with a parameter of 0)
• the growBy of 500 means that we take steps based on 500ms

This yields the following delays: `0ms, 500ms, 1s, 2s, 4s, 4s, 4s,…`

In detail : `0, 500 * 2^0, 500 * 2^1, 500 * 2^2, 500 * 2^3, max(4000, 500 * 2^4), max(4000, 500 * 2^5),…`.

Finally, the powers used in the computation can be changed from powers of two by default to another base using the powersOf parameter.

Since:
1.1.0
Author:
Michael Nitschinger
• ### Method Summary

All Methods
Modifier and Type Method and Description
`long` `calculate(long attempt)`
Calculate a specific delay based on the attempt passed in.
`protected long` `calculateAlternatePower(long attempt)`
`protected long` `calculatePowerOfTwo(long attempt)`
`String` `toString()`
• ### Methods inherited from class com.couchbase.client.core.time.Delay

`exponential, exponential, exponential, exponential, exponential, fixed, linear, linear, linear, linear, unit`
• ### Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`
• ### Method Detail

• #### calculate

`public long calculate(long attempt)`
Description copied from class: `Delay`

Calculate a specific delay based on the attempt passed in.

This method is to be implemented by the child implementations and depending on the params that were set during construction time.

Specified by:
`calculate` in class `Delay`
Parameters:
`attempt` - the attempt to calculate the delay from.
Returns:
the calculate delay.
• #### calculateAlternatePower

`protected long calculateAlternatePower(long attempt)`
• #### calculatePowerOfTwo

`protected long calculatePowerOfTwo(long attempt)`
• #### toString

`public String toString()`
Overrides:
`toString` in class `Object`