org.apache.storm.kafka.spout

## Class KafkaSpoutRetryExponentialBackoff

- java.lang.Object
- - org.apache.storm.kafka.spout.KafkaSpoutRetryExponentialBackoff

- All Implemented Interfaces:
    Serializable, KafkaSpoutRetryService

      public class KafkaSpoutRetryExponentialBackoff
      extends Object
      implements KafkaSpoutRetryService

  Implementation of `KafkaSpoutRetryService` using the exponential backoff formula. The time of the nextRetry is set as follows: nextRetry = failCount == 1 ? currentTime + initialDelay : currentTime + delayPeriod*2^(failCount-1) where failCount = 1, 2, 3, … nextRetry = Min(nextRetry, currentTime + maxDelay)

  See Also:
    Serialized Form

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `KafkaSpoutRetryExponentialBackoff.TimeInterval`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `KafkaSpoutRetryExponentialBackoff(KafkaSpoutRetryExponentialBackoff.TimeInterval initialDelay, KafkaSpoutRetryExponentialBackoff.TimeInterval delayPeriod, int maxRetries, KafkaSpoutRetryExponentialBackoff.TimeInterval maxDelay)` The time stamp of the next retry is scheduled according to the exponential backoff formula (geometric progression): nextRetry = failCount == 1 ? currentTime + initialDelay : currentTime + delayPeriod^(failCount-1), where failCount = 1, 2, 3, … nextRetry = Min(nextRetry, currentTime + maxDelay).

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Map<org.apache.kafka.common.TopicPartition,Long>` | `earliestRetriableOffsets()` Gets the earliest retriable offsets.
    `KafkaSpoutMessageId` | `getMessageId(org.apache.kafka.common.TopicPartition tp, long offset)` Gets the `KafkaSpoutMessageId` for the record on the given topic partition and offset.
    `boolean` | `isReady(KafkaSpoutMessageId msgId)` Checks if a specific failed `KafkaSpoutMessageId` is ready to be retried, i.e is scheduled and has retry time that is less than current time.
    `boolean` | `isScheduled(KafkaSpoutMessageId msgId)` Checks if a specific failed `KafkaSpoutMessageId` is scheduled to be retried.
    `int` | `readyMessageCount()` Get the number of messages ready for retry.
    `boolean` | `remove(KafkaSpoutMessageId msgId)` Removes a message from the list of messages scheduled for retrial.
    `boolean` | `retainAll(Collection<org.apache.kafka.common.TopicPartition> topicPartitions)` Retains all the messages whose `TopicPartition` belongs to the specified `Collection<TopicPartition>`.
    `boolean` | `schedule(KafkaSpoutMessageId msgId)` Schedules this `KafkaSpoutMessageId` if not yet scheduled, or updates retry time if it has already been scheduled.
    `String` | `toString()`

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### KafkaSpoutRetryExponentialBackoff

          public KafkaSpoutRetryExponentialBackoff(KafkaSpoutRetryExponentialBackoff.TimeInterval initialDelay,
                                                   KafkaSpoutRetryExponentialBackoff.TimeInterval delayPeriod,
                                                   int maxRetries,
                                                   KafkaSpoutRetryExponentialBackoff.TimeInterval maxDelay)

      The time stamp of the next retry is scheduled according to the exponential backoff formula (geometric progression): nextRetry = failCount == 1 ? currentTime + initialDelay : currentTime + delayPeriod^(failCount-1), where failCount = 1, 2, 3, … nextRetry = Min(nextRetry, currentTime + maxDelay).

      By specifying a value for maxRetries lower than Integer.MAX_VALUE, the user decides to sacrifice guarantee of delivery for the previous polled records in favor of processing more records.
      Parameters:
        `initialDelay` - initial delay of the first retry
        `delayPeriod` - the time interval that is the ratio of the exponential backoff formula (geometric progression)
        `maxRetries` - maximum number of times a tuple is retried before being acked and scheduled for commit
        `maxDelay` - maximum amount of time waiting before retrying

  - ### Method Detail

    - #### earliestRetriableOffsets

          public Map<org.apache.kafka.common.TopicPartition,Long> earliestRetriableOffsets()

      Description copied from interface: `KafkaSpoutRetryService`

      Gets the earliest retriable offsets.

      Specified by:
        `earliestRetriableOffsets` in interface `KafkaSpoutRetryService`
      Returns:
        The earliest retriable offset for each TopicPartition that has offsets ready to be retried, i.e. for which a tuple has failed and has retry time less than current time.

    - #### isReady

          public boolean isReady(KafkaSpoutMessageId msgId)

      Description copied from interface: `KafkaSpoutRetryService`

      Checks if a specific failed `KafkaSpoutMessageId` is ready to be retried, i.e is scheduled and has retry time that is less than current time.

      Specified by:
        `isReady` in interface `KafkaSpoutRetryService`
      Parameters:
        `msgId` - message to check for readiness
      Returns:
        true if message is ready to be retried, false otherwise

    - #### isScheduled

          public boolean isScheduled(KafkaSpoutMessageId msgId)

      Description copied from interface: `KafkaSpoutRetryService`

      Checks if a specific failed `KafkaSpoutMessageId` is scheduled to be retried. The message may or may not be ready to be retried yet.

      Specified by:
        `isScheduled` in interface `KafkaSpoutRetryService`
      Parameters:
        `msgId` - message to check for scheduling status
      Returns:
        true if the message is scheduled to be retried, regardless of being or not ready to be retried. Returns false is this message is not scheduled for retrial

    - #### remove

          public boolean remove(KafkaSpoutMessageId msgId)

      Description copied from interface: `KafkaSpoutRetryService`

      Removes a message from the list of messages scheduled for retrial.

      Specified by:
        `remove` in interface `KafkaSpoutRetryService`
      Parameters:
        `msgId` - message to remove from retrial
      Returns:
        true if the message was scheduled for retrial, false otherwise

    - #### retainAll

          public boolean retainAll(Collection<org.apache.kafka.common.TopicPartition> topicPartitions)

      Description copied from interface: `KafkaSpoutRetryService`

      Retains all the messages whose `TopicPartition` belongs to the specified `Collection<TopicPartition>`. All messages that come from a `TopicPartition` NOT existing in the collection will be removed. This method is useful to cleanup state following partition rebalance.

      Specified by:
        `retainAll` in interface `KafkaSpoutRetryService`
      Parameters:
        `topicPartitions` - Collection of `TopicPartition` for which to keep messages
      Returns:
        true if at least one message was removed, false otherwise

    - #### schedule

          public boolean schedule(KafkaSpoutMessageId msgId)

      Description copied from interface: `KafkaSpoutRetryService`

      Schedules this `KafkaSpoutMessageId` if not yet scheduled, or updates retry time if it has already been scheduled. It may also indicate that the message should not be retried, in which case the message will not be scheduled.

      Specified by:
        `schedule` in interface `KafkaSpoutRetryService`
      Parameters:
        `msgId` - message to schedule for retrial
      Returns:
        true if the message will be retried, false otherwise

    - #### readyMessageCount

          public int readyMessageCount()

      Description copied from interface: `KafkaSpoutRetryService`

      Get the number of messages ready for retry.

      Specified by:
        `readyMessageCount` in interface `KafkaSpoutRetryService`
      Returns:
        The number of messages that are ready for retry

    - #### getMessageId

          public KafkaSpoutMessageId getMessageId(org.apache.kafka.common.TopicPartition tp,
                                                  long offset)

      Description copied from interface: `KafkaSpoutRetryService`

      Gets the `KafkaSpoutMessageId` for the record on the given topic partition and offset.

      Specified by:
        `getMessageId` in interface `KafkaSpoutRetryService`
      Parameters:
        `tp` - The topic partition of the record
        `offset` - The offset of the record
      Returns:
        The id the record was scheduled for retry with, or a new `KafkaSpoutMessageId` if the record was not scheduled for retry.

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

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