Package io.smallrye.faulttolerance.api

Annotation Type ExponentialBackoff

@Inherited @Documented @Retention(RUNTIME) @Target({METHOD,TYPE}) @Experimental("first attempt at providing additional retry backoff strategies") public @interface ExponentialBackoff
Modifies a @Retry annotation to use exponential backoff instead of the default constant backoff. May only be present on elements that are also annotated @Retry.

Exponential backoff uses the initial delay before the first retry attempt, and then increases the delays exponentially. With the default factor of 2, the first few delays are: initial delay, 2 * initial delay, 4 * initial delay, 8 * initial delay, 16 * initial delay, 32 * initial delay, etc. (Additionally, jitter will be applied to each value.) To prevent unbounded growth of these delays, maxDelay() should be configured.

All configuration options of @Retry still apply and all their constraints are still enforced. Additionally:

  • delay, delayUnit: is used as an initial delay, before the first retry attempt. Must be less than maxDelay(). Note that if 0, exponential backoff degenerates to zero backoff.
See Also:

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    int
    factor
    The multiplicative factor used when determining a delay between two retries.
    long
    maxDelay
    The maximum delay between retries.
    ChronoUnit
    maxDelayUnit
    The unit for maxDelay().

  • Element Details

    • factor

      int factor
      The multiplicative factor used when determining a delay between two retries. A delay is computed as factor * previousDelay, resulting in an exponential growth.

      The value must be greater than or equal to 1 (though with factor of 1, exponential backoff degenerates to constant backoff).

      Returns:
      the growth factor
      Default:
      2

    • maxDelay

      long maxDelay
      The maximum delay between retries. Defaults to 1 minute. The value must be greater than or equal to 0, and must be less than Retry.maxDuration (if that is set). 0 means not set.

      Note that this is different from maxDuration. This places a limit on each individual delay between retries, while maxDuration places a limit on the total time all retries may take.

      Returns:
      the max delay time
      Default:
      60000L

    • maxDelayUnit

      ChronoUnit maxDelayUnit
      The unit for maxDelay(). Defaults to ChronoUnit.MILLIS.
      Returns:
      the max delay unit
      Default:
      MILLIS