io.cdap.cdap.api.messaging

Interface MessagingContext

All Known Subinterfaces:

CustomActionContext, HttpServiceContext, MapReduceContext, ServiceContext, SparkClientContext, WorkerContext, WorkflowContext

@Beta
public interface MessagingContext

Provides access to the Transactional Messaging System.

Method Summary

Modifier and Type	Method and Description
MessagePublisher	getDirectMessagePublisher() Returns an instance of MessagePublisher for publishing messages without a transaction.
MessageFetcher	getMessageFetcher() Returns an instance of MessageFetcher for fetching messages.
MessagePublisher	getMessagePublisher() Returns an instance of MessagePublisher for publishing messages.

Method Detail

getMessagePublisher

MessagePublisher getMessagePublisher()

Returns an instance of MessagePublisher for publishing messages.

Messages will be published transactionally if any of the publish methods in the MessagePublisher are called from a transactional context (either through Implicit Transaction Control, or Transactional.execute(TxRunnable) when Explicit Transaction Control is used).

When those publish methods are called without a transactional context, the message will be published without a transaction.

Returns:

a new instance of MessagePublisher. The returned instance cannot be shared across multiple threads.

getDirectMessagePublisher

MessagePublisher getDirectMessagePublisher()

Returns an instance of MessagePublisher for publishing messages without a transaction.

Messages published through the resulting MessagePublisher are always published without using a transaction and are immediately available for consumption.

Returns:

a new instance of MessagePublisher. The returned instance is safe to be used from multiple threads.

getMessageFetcher

MessageFetcher getMessageFetcher()

Returns an instance of MessageFetcher for fetching messages.

Messages will be fetched transactionally if any of the fetch methods in the MessageFetcher are called from a transactional context (either through Implicit Transaction Control, or Transactional.execute(TxRunnable) when Explicit Transaction Control is used).

When those fetch methods are called without a transactional context, the message will be fetched without a transaction.

Returns:

a new instance of MessageFetcher. The returned instance cannot be shared across multiple threads.