io.nats.client

Interface Subscription

All Superinterfaces:

AutoCloseable

All Known Subinterfaces:

AsyncSubscription, SyncSubscription

public interface Subscription
extends AutoCloseable

A client uses a Subscription object to receive messages that have been published to a subject.

Each Subscription object is unique, even if the subscription is to the same subject. This means that if Connection.subscribe("foo", cb) is called twice in a row, each of the resulting Subscription objects will be unique, and any message delivered on subject "foo" will be delivered individually to both Subscription objects.

Method Summary

Modifier and Type	Method and Description
void	autoUnsubscribe(int max) Issues an automatic unsubscribe request.
void	close()
int	getDropped() Returns the number of messages that this subscription has dropped due to "slow consumer" condition.
long	getMaxPendingBytes() Returns the maximum number of pending bytes for this subscription.
int	getMaxPendingMsgs() Returns the maximum number of pending messages for this subscription.
String	getQueue() Returns the optional queue group name.
int	getQueuedMessageCount() Returns the number of messages delivered to, but not processed, by this Subscription.
String	getSubject() Retrieves the subject of interest from the Subscription object.
boolean	isValid() Returns whether the Subscription object is still active (subscribed).
void	setMaxPendingBytes(long pending) Sets the maximum number of unprocessed message bytes that can be left pending on this subscription before a slow consumer exception is thrown.
void	setMaxPendingMsgs(int pending) Sets the maximum number of unprocessed messages that can be left pending on this subscription before a slow consumer exception is thrown.
void	setPendingLimits(int msgs, int bytes) Sets the the maximum number of unprocessed messages and bytes that can be left pending on this subscription before messages are dropped and a slow consumer exception is thrown.
void	unsubscribe() Removes interest in the Subscription object's subject immediately.

Method Detail

getSubject

String getSubject()

Retrieves the subject of interest from the Subscription object.

Returns:

the subject of interest

getQueue

String getQueue()

Returns the optional queue group name. If present, all subscriptions with the same name will form a distributed queue, and each message will only be processed by one member of the group.

Returns:

the name of the queue group this Subscription belongs to.

isValid

boolean isValid()

Returns whether the Subscription object is still active (subscribed).

Returns:

true if the Subscription is active, false otherwise.

unsubscribe

void unsubscribe()
          throws IOException

Removes interest in the Subscription object's subject immediately.

Throws:

IOException - if an error occurs while notifying the server

autoUnsubscribe

void autoUnsubscribe(int max)
              throws IOException

Issues an automatic unsubscribe request. The unsubscribe is executed by the server when max messages have been received. This can be useful when sending a request to an unknown number of subscribers. request() uses this functionality.

Parameters:

max - The number of messages to receive before unsubscribing.

Throws:

IOException - if an error occurs while sending the unsubscribe request to the NATS server.

getQueuedMessageCount

int getQueuedMessageCount()

Returns the number of messages delivered to, but not processed, by this Subscription.

Returns:

the number of delivered messages.

getMaxPendingMsgs

int getMaxPendingMsgs()

Returns the maximum number of pending messages for this subscription.

Returns:

the maximum number of pending messages for this subscription

getMaxPendingBytes

long getMaxPendingBytes()

Returns the maximum number of pending bytes for this subscription.

Returns:

the maximum number of pending bytes for this subscription

setMaxPendingMsgs

void setMaxPendingMsgs(int pending)

Sets the maximum number of unprocessed messages that can be left pending on this subscription before a slow consumer exception is thrown.

Parameters:

pending - the maximum number of pending messages

setMaxPendingBytes

void setMaxPendingBytes(long pending)

Sets the maximum number of unprocessed message bytes that can be left pending on this subscription before a slow consumer exception is thrown.

Parameters:

pending - the maximum number of pending bytes

setPendingLimits

void setPendingLimits(int msgs,
                      int bytes)

Sets the the maximum number of unprocessed messages and bytes that can be left pending on this subscription before messages are dropped and a slow consumer exception is thrown.

Parameters:

msgs - the maximum number of pending messages

bytes - the maximum number of pending bytes

getDropped

int getDropped()

Returns the number of messages that this subscription has dropped due to "slow consumer" condition.

Returns:

the number of messages that have been dropped by this Subscription

close

void close()

Specified by:

close in interface AutoCloseable