Package com.cloudera.cdp.http

Class ExponentialBackoffDelayPolicy

java.lang.Object

com.cloudera.cdp.http.ExponentialBackoffDelayPolicy

All Implemented Interfaces:

DelayPolicy

public class ExponentialBackoffDelayPolicy
extends Object
implements DelayPolicy

Implement an exponential backoff policy. For a given 'base' and 'growthFactor' a delay will be computed to be:

'base' * 'growthFactor' ^ (attempts - 1)

For example:

• base = 500ms, growthFactor = 2
• attempts = 1, delay = 500 * 2^0 = 500ms
• attempts = 2, delay = 500 * 2^1 = 1sec
• attempts = 3, delay = 500 * 2^2 = 2sec

Optional jitter causes each computed delay to vary from its deterministic value, as computed above, up to a certain percentage. For example:

• base = 500ms, growthFactor = 2, jitterPercentage = 5
• attempts = 1, delay = 500 * 2^0 +/- 25ms = 475ms - 525ms
• attempts = 2, delay = 500 * 2^1 +/- 50ms = 900ms - 1100ms
• attempts = 3, delay = 500 * 2^2 +/- 100ms= 1.9sec - 2.1sec

Constructor Summary

Constructors

Constructor	Description
ExponentialBackoffDelayPolicy(int growthFactor, Duration base)	Constructs an exponential backoff delay policy with the given 'growthFactor' and 'base'.
ExponentialBackoffDelayPolicy(int growthFactor, Duration base, int jitterPercentage)	Constructs an exponential backoff delay policy with the given 'growthFactor', 'base', and 'jitterPercentage'.

Method Summary

Modifier and Type	Method	Description
Duration	delay(int attempts)	Returns the delay needed before attempting the next retry.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ExponentialBackoffDelayPolicy

public ExponentialBackoffDelayPolicy(int growthFactor,
 Duration base)

Constructs an exponential backoff delay policy with the given 'growthFactor' and 'base'. There is no jitter applied.

Parameters:

growthFactor - The growth factor between delays. Must be positive

base - The base. Must be a positive duration.

ExponentialBackoffDelayPolicy

public ExponentialBackoffDelayPolicy(int growthFactor,
 Duration base,
 int jitterPercentage)

Constructs an exponential backoff delay policy with the given 'growthFactor', 'base', and 'jitterPercentage'.

Parameters:

growthFactor - The growth factor between delays. Must be positive

base - The base. Must be a positive duration.

jitterPercentage - Percentage of jitter range applied to delay. Must non-negative.

Method Details

delay

public Duration delay(int attempts)

Description copied from interface: DelayPolicy

Returns the delay needed before attempting the next retry.

Specified by:

delay in interface DelayPolicy

Parameters:

attempts - The number of attempts made to make the call

Returns:

The duration to wait