org.springframework.retry.annotation

Annotation Type Backoff

@Target(value=TYPE)
 @Retention(value=RUNTIME)
 @Import(value=RetryConfiguration.class)
 @Documented
public @interface Backoff

Collects metadata for a BackOffPolicy. Features:

• With no explicit settings the default is a fixed delay of 1000ms
• Only the delay() set: the backoff is a fixed delay with that value
• When delay() and maxDelay() are set the backoff is uniformly distributed between the two values
• With delay(), maxDelay() and multiplier() the backoff is exponentially growing up to the maximum value
• If, in addition, the random() flag is set then the multiplier is chosen for each delay from a uniform distribution in [1, multiplier-1]

Since:

1.1

Author:

Dave Syer, Gary Russell

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
long	delay A canonical backoff period.
String	delayExpression An expression evaluating to the canonical backoff period.
long	maxDelay The maximimum wait (in milliseconds) between retries.
String	maxDelayExpression An expression evaluating to the maximimum wait (in milliseconds) between retries.
double	multiplier If positive, then used as a multiplier for generating the next delay for backoff.
String	multiplierExpression Evaluates to a vaule used as a multiplier for generating the next delay for backoff.
boolean	random In the exponential case (multiplier() > 0) set this to true to have the backoff delays randomized, so that the maximum delay is multiplier times the previous delay and the distribution is uniform between the two values.
long	value Synonym for delay().

Element Detail

value

public abstract long value

Synonym for delay().

Returns:

the delay in milliseconds (default 1000)

Default:

1000L

delay

public abstract long delay

A canonical backoff period. Used as an initial value in the exponential case, and as a minimum value in the uniform case.

Returns:

the initial or canonical backoff period in milliseconds (default 1000)

Default:

0L

maxDelay

public abstract long maxDelay

The maximimum wait (in milliseconds) between retries. If less than the delay() then the default of 30000L is applied.

Returns:

the maximum delay between retries (default 0 = ignored)

Default:

0L

multiplier

public abstract double multiplier

If positive, then used as a multiplier for generating the next delay for backoff.

Returns:

a multiplier to use to calculate the next backoff delay (default 0 = ignored)

Default:

0.0

delayExpression

public abstract String delayExpression

An expression evaluating to the canonical backoff period. Used as an initial value in the exponential case, and as a minimum value in the uniform case. Overrides delay().

Returns:

the initial or canonical backoff period in milliseconds.

Since:

1.2

Default:

""

maxDelayExpression

public abstract String maxDelayExpression

An expression evaluating to the maximimum wait (in milliseconds) between retries. If less than the delay() then the default of 30000L is applied. Overrides maxDelay()

Returns:

the maximum delay between retries (default 0 = ignored)

Since:

1.2

Default:

""

multiplierExpression

public abstract String multiplierExpression

Evaluates to a vaule used as a multiplier for generating the next delay for backoff. Overrides multiplier().

Returns:

a multiplier expression to use to calculate the next backoff delay (default 0 = ignored)

Since:

1.2

Default:

""

random

public abstract boolean random

In the exponential case (multiplier() > 0) set this to true to have the backoff delays randomized, so that the maximum delay is multiplier times the previous delay and the distribution is uniform between the two values.

Returns:

the flag to signal randomization is required (default false)

Default:

false