Examples of ExponentialBackoffPolicy

com.google.api.client.http.ExponentialBackOffPolicy
Implementation of {@link BackOffPolicy} that increases the back off period for each retry attemptusing a randomization function that grows exponentially.
{@link #getNextBackOffMillis()} is calculated using the following formula:
```
 randomized_interval = retry_interval * (random value in range [1 - randomization_factor, 1 + randomization_factor]) 
```
In other words {@link #getNextBackOffMillis()} will range between the randomization factorpercentage below and above the retry interval. For example, using 2 seconds as the base retry interval and 0.5 as the randomization factor, the actual back off period used in the next retry attempt will be between 1 and 3 seconds.

Note: max_interval caps the retry_interval and not the randomized_interval.

If the time elapsed since an {@link ExponentialBackOffPolicy} instance is created goes past themax_elapsed_time then the method {@link #getNextBackOffMillis()} starts returning{@link BackOffPolicy#STOP}. The elapsed time can be reset by calling {@link #reset()}.

Example: The default retry_interval is .5 seconds, default randomization_factor is 0.5, default multiplier is 1.5 and the default max_interval is 1 minute. For 10 requests the sequence will be (values in seconds) and assuming we go over the max_elapsed_time on the 10th request:
```
 request#     retry_interval     randomized_interval 1             0.5                [0.25,   0.75] 2             0.75               [0.375,  1.125] 3             1.125              [0.562,  1.687] 4             1.687              [0.8435, 2.53] 5             2.53               [1.265,  3.795] 6             3.795              [1.897,  5.692] 7             5.692              [2.846,  8.538] 8             8.538              [4.269, 12.807] 9            12.807              [6.403, 19.210] 10           19.210               {@link BackOffPolicy#STOP}
```
Implementation is not thread-safe.
@since 1.7 @author Ravi Mistry
org.apache.hadoop.hbase.util.RetryCounter.ExponentialBackoffPolicy
org.springframework.retry.backoff.ExponentialBackOffPolicy
Implementation of {@link BackOffPolicy} that increases the back off periodfor each retry attempt in a given set using the {@link Math#exp(double) exponential} function.
This implementation is thread-safe and suitable for concurrent access. Modifications to the configuration do not affect any retry sets that are already in progress.
The {@link #setInitialInterval(long)} property controls the initial valuepassed to {@link Math#exp(double)} and the {@link #setMultiplier(double)}property controls by how much this value is increased for each subsequent attempt. @author Rob Harrop @author Dave Syer @author Gary Russell @author Artem Bilan

Examples of org.springframework.retry.backoff.ExponentialBackOffPolicy

  @Test
  public void testSimulatorExercisesRandomExponentialBackoff() {
    SimpleRetryPolicy retryPolicy = new SimpleRetryPolicy();
    retryPolicy.setMaxAttempts(5);


    ExponentialBackOffPolicy backOffPolicy = new ExponentialRandomBackOffPolicy();
    backOffPolicy.setMultiplier(2);
    backOffPolicy.setMaxInterval(30000);
    backOffPolicy.setInitialInterval(100);


    RetrySimulator simulator = new RetrySimulator(backOffPolicy, retryPolicy);
    RetrySimulation simulation = simulator.executeSimulation(10000);
    System.out.println(backOffPolicy);
    System.out.println("Longest sequence  " + simulation.getLongestTotalSleepSequence());

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Examples of org.springframework.retry.backoff.ExponentialBackOffPolicy

   * @return this.
   */
  public RetryInterceptorBuilder<T> backOffOptions(long initialInterval, double multiplier , long maxInterval) {
    Assert.isNull(this.retryOperations, "cannot set the back off policy when a custom retryOperations has been set");
    Assert.isTrue(!this.backOffPolicySet, "cannot set the back off options when a back off policy has been set");
    ExponentialBackOffPolicy policy = new ExponentialBackOffPolicy();
    policy.setInitialInterval(initialInterval);
    policy.setMultiplier(multiplier);
    policy.setMaxInterval(maxInterval);
    this.retryTemplate.setBackOffPolicy(policy);
    this.backOffOptionsSet = true;
    this.templateAltered = true;
    return this;
  }

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