io.nats.client

Interface JetStreamSubscription

All Superinterfaces:

Consumer, Subscription

public interface JetStreamSubscription
extends Subscription

Subscription on a JetStream context.

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_PULL_SIZE The maximum pull size

Fields inherited from interface io.nats.client.Consumer

DEFAULT_MAX_BYTES, DEFAULT_MAX_MESSAGES

Method Summary

Modifier and Type	Method and Description
java.util.List<Message>	fetch(int batchSize, java.time.Duration maxWait) Fetch a list of messages up to the batch size, waiting no longer than maxWait.
ConsumerInfo	getConsumerInfo() Gets information about the consumer behind this subscription.
java.util.Iterator<Message>	iterate(int batchSize, java.time.Duration maxWait) Prepares an iterator.
void	pull(int batchSize) Polls for new messages, overriding the default batch size for this pull only.
void	pullExpiresIn(int batchSize, java.time.Duration expiresIn) Initiate pull for all messages available before expiration.
void	pullNoWait(int batchSize) Do a pull in noWait mode with the specified batch size.

Methods inherited from interface io.nats.client.Subscription

getDispatcher, getQueueName, getSubject, nextMessage, unsubscribe, unsubscribe

Methods inherited from interface io.nats.client.Consumer

clearDroppedCount, drain, getDeliveredCount, getDroppedCount, getPendingByteCount, getPendingByteLimit, getPendingMessageCount, getPendingMessageLimit, isActive, setPendingLimits

Field Detail

MAX_PULL_SIZE

static final int MAX_PULL_SIZE

The maximum pull size

See Also:

Constant Field Values

Method Detail

pull

void pull(int batchSize)

Polls for new messages, overriding the default batch size for this pull only. This should only be used when the subscription is pull based.

Parameters:

batchSize - the size of the batch

pullNoWait

void pullNoWait(int batchSize)

Do a pull in noWait mode with the specified batch size. When true a response with a 404 status header will be returned when no messages are available. This can only be used when the subscription is pull based.

Parameters:

batchSize - the size of the batch

pullExpiresIn

void pullExpiresIn(int batchSize,
                   java.time.Duration expiresIn)

Initiate pull for all messages available before expiration. This can only be used when the subscription is pull based.

sub.nextMessage(timeout) can return a:

• regular message
• null
• 408 status message

Multiple 408 status messages may come. Each one indicates a missing item from the previous batch and can be discarded.

Parameters:

batchSize - the size of the batch

expiresIn - how long from now this request should be expired from the server wait list

fetch

java.util.List<Message> fetch(int batchSize,
                              java.time.Duration maxWait)

Fetch a list of messages up to the batch size, waiting no longer than maxWait. This uses pullExpiresIn under the covers, and manages all responses from sub.nextMessage(...) to only return regular JetStream messages. This can only be used when the subscription is pull based.

Parameters:

batchSize - the size of the batch

maxWait - the maximum time to wait for the first message.

Returns:

the list of messages

iterate

java.util.Iterator<Message> iterate(int batchSize,
                                    java.time.Duration maxWait)

Prepares an iterator. This uses pullExpiresIn under the covers, and manages all responses. The iterator will have no messages if it does not receive the first message within the max wait period. It will stop if the batch is fulfilled or if there are fewer than batch size messages. 408 Status messages are ignored and will not count toward the fulfilled batch size.

Parameters:

batchSize - the size of the batch

maxWait - the maximum time to wait for the first message.

Returns:

the message iterator

getConsumerInfo

ConsumerInfo getConsumerInfo()
                      throws java.io.IOException,
                             JetStreamApiException

Gets information about the consumer behind this subscription.

Returns:

consumer information

Throws:

java.io.IOException - covers various communication issues with the NATS server such as timeout or interruption

JetStreamApiException - the request had an error related to the data