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trait DynamoDBTransactHandler[Envelope] extends HandlerLifecycle

Implement this interface for the Envelope handler for DynamoDB transactional projections.

It can be stateful, with variables and mutable data structures. It is invoked by the Projection machinery one envelope at a time and visibility guarantees between the invocations are handled automatically, i.e. no volatile or other concurrency primitives are needed for managing the state.

Supported error handling strategies for when processing an Envelope fails can be defined in configuration or using the withRecoveryStrategy method of a Projection implementation.

Annotations
@ApiMayChange()
Source
DynamoDBTransactHandler.scala
Linear Supertypes
HandlerLifecycle, AnyRef, Any
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Inherited
  1. DynamoDBTransactHandler
  2. HandlerLifecycle
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Visibility
  1. Public
  2. Protected

Abstract Value Members

  1. abstract def process(envelope: Envelope): CompletionStage[Collection[TransactWriteItem]]

    The process method is invoked for each Envelope, and should return DynamoDB TransactWriteItems to atomically write along with the projection offset.

    The process method is invoked for each Envelope, and should return DynamoDB TransactWriteItems to atomically write along with the projection offset.

    One envelope is processed at a time. It will not be invoked with the next envelope until the returned CompletionStage has completed and the given items written in a transaction.

Concrete Value Members

  1. def start(): CompletionStage[Done]

    Invoked when the projection is starting, before first envelope is processed.

    Invoked when the projection is starting, before first envelope is processed. Can be overridden to implement initialization.

    Definition Classes
    DynamoDBTransactHandler → HandlerLifecycle
  2. def stop(): CompletionStage[Done]

    Invoked when the projection has been stopped.

    Invoked when the projection has been stopped. Can be overridden to implement resource cleanup.

    Definition Classes
    DynamoDBTransactHandler → HandlerLifecycle