Annotation Interface BackOff

@Target(ANNOTATION_TYPE)
@Retention(RUNTIME)
@Documented
public @interface BackOff

Collects metadata for creating a BackOff instance as part of a RetryPolicy. Values can be provided as is or using a *String equivalent that supports more format, as well as expression evaluations.

The available attributes lead to the following:

• With no explicit settings, the default is a FixedBackOff with a delay of 1000L ms
• With only delay() set: a fixed delay back off with that value
• In all other cases, an ExponentialBackOff is created with the values of delay() (default: 1000L ms), maxDelay() (default: no maximum), multiplier() (default: 1.0) and jitter() (default: no jitter).

Since:

4.0

Author:

Dave Syer, Gary Russell, Aftab Shaikh, Stephane Nicoll

Field Summary

Fields

Modifier and Type	Field	Description
static final long	DEFAULT_DELAY	Default delay() in milliseconds.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
long	delay	Specify the base delay after the initial invocation.
String	delayString	Specify the base delay after the initial invocation using a String format.
long	jitter	Specify a jitter value for the base retry attempt, randomly subtracted or added to the calculated delay, resulting in a value between delay - jitter and delay + jitter but never below the base delay or above the max delay.
String	jitterString	Specify a jitter value for the base retry attempt using a String format.
long	maxDelay	Specify the maximum delay for any retry attempt, limiting how far jitter and the multiplier can increase the delay.
String	maxDelayString	Specify the maximum delay for any retry attempt using a String format.
double	multiplier	Specify a multiplier for a delay for the next retry attempt, applied to the previous delay, starting with the initial delay as well as to the applicable jitter for each attempt.
String	multiplierString	Specify a multiplier for a delay for the next retry attempt using a String format.
long	value	Alias for delay().

Field Details

DEFAULT_DELAY

static final long DEFAULT_DELAY

Default delay() in milliseconds.

See Also:

• Constant Field Values

Element Details

value

@AliasFor("delay")
long value

Alias for delay().

Intended to be used when no other attributes are needed, for example: @BackOff(2000).

Returns:

the based delay in milliseconds (default1000L)

Default:

1000L

delay

@AliasFor("value")
long delay

Specify the base delay after the initial invocation.

If only a delay is specified, a FixedBackOff with that value as the interval is configured.

If a multiplier is specified, this serves as the initial delay to multiply from.

The default is 1000L milliseconds.

Returns:

the based delay in milliseconds (default1000L)

Default:

1000L

delayString

String delayString

Specify the base delay after the initial invocation using a String format. If this is specified, takes precedence over delay().

The delay String can be in several formats:

• a plain long — which is interpreted to represent a duration in milliseconds
• any of the known DurationFormat.Style: the ISO8601 style or the SIMPLE style — using milliseconds as fallback if the string doesn't contain an explicit unit
• Regular expressions, such as ${example.property} to use the example.property from the environment

Returns:

the based delay as a String value — for example a placeholder

See Also:

• delay()

Default:

""

maxDelay

long maxDelay

Specify the maximum delay for any retry attempt, limiting how far jitter and the multiplier can increase the delay.

Ignored if only delay() is set, otherwise an ExponentialBackOff with the given max delay or an unlimited delay if not set.

Returns:

the maximum delay

Default:

0L

maxDelayString

String maxDelayString

Specify the maximum delay for any retry attempt using a String format. If this is specified, takes precedence over maxDelay()..

The max delay String can be in several formats:

• a plain long — which is interpreted to represent a duration in milliseconds
• any of the known DurationFormat.Style: the ISO8601 style or the SIMPLE style — using milliseconds as fallback if the string doesn't contain an explicit unit
• Regular expressions, such as ${example.property} to use the example.property from the environment

Returns:

the max delay as a String value — for example a placeholder

See Also:

• maxDelay()

Default:

""

multiplier

double multiplier

Specify a multiplier for a delay for the next retry attempt, applied to the previous delay, starting with the initial delay as well as to the applicable jitter for each attempt.

Ignored if only delay() is set, otherwise an ExponentialBackOff with the given multiplier or 1.0 if not set.

Returns:

the value to multiply the current interval by for each attempt

Default:

0.0

multiplierString

String multiplierString

Specify a multiplier for a delay for the next retry attempt using a String format. If this is specified, takes precedence over multiplier().

The multiplier String can be in several formats:

• a plain double
• Regular expressions, such as ${example.property} to use the example.property from the environment

Returns:

the value to multiply the current interval by for each attempt — for example, a placeholder

See Also:

• multiplier()

Default:

""

jitter

long jitter

Specify a jitter value for the base retry attempt, randomly subtracted or added to the calculated delay, resulting in a value between delay - jitter and delay + jitter but never below the base delay or above the max delay.

If a multiplier is specified, it is applied to the jitter value as well.

Ignored if only delay() is set, otherwise an ExponentialBackOff with the given jitter or no jitter if not set.

Returns:

the jitter value in milliseconds

See Also:

• delay()
• maxDelay()
• multiplier()

Default:

0L

jitterString

String jitterString

Specify a jitter value for the base retry attempt using a String format. If this is specified, takes precedence over jitter().

The jitter String can be in several formats:

• a plain long — which is interpreted to represent a duration in milliseconds
• any of the known DurationFormat.Style: the ISO8601 style or the SIMPLE style — using milliseconds as fallback if the string doesn't contain an explicit unit
• Regular expressions, such as ${example.property} to use the example.property from the environment

Returns:

the jitter as a String value — for example, a placeholder

See Also:

• jitter()

Default:

""