WebLogic Messaging API Class Library |

# ISession.CreateDurableSubscriber Method (ITopic, String, String, Boolean)

Creates a durable subscriber to the specified topic, using a message selector and specifying whether messages published by its own connection should be delivered to it.

If a client needs to receive all the messages published on a topic, including the ones published while the subscriber is inactive, it uses a durable `IMessageConsumer`. The JMS server retains a record of this durable subscription and insures that all messages from the topic's publishers are retained until they are acknowledged by this durable subscriber or they have expired.

Sessions with durable subscribers must always provide the same client identifier. In addition, each client must specify a name which uniquely identifies (within client identifier) each durable subscription it creates. Only one session at a time can have a `IMessageConsumer` for a particular durable subscription. An inactive durable subscriber is one that exists but does not currently have a message consumer associated with it.

A client can change an existing durable subscription by creating a durable `IMessageConsumer` with the same name and a new topic and/or message selector. Changing a durable subscriber is equivalent to unsubscribing (deleting) the old one and creating a new one.

IMessageConsumer CreateDurableSubscriber(
ITopic topic,
String name,
String messageSelector,
Boolean noLocal
);

#### Parameters

ITopic
  the non-temporary `ITopic` to subscribe to
String
  the name used to identify this subscription
String
  only messages with properties matching the message selector expression are delivered. A value of null or an empty string indicates that there is no message selector for the message consumer.
Boolean
  if set, inhibits the delivery of messages published by its own connection

#### Return Value

An `IMessageConsumer` for the specified destination

#### Remarks

Warning: Delete unused durable subscriptions using `ISession.Unsubscribe`. Unused durable subscriptions continue to accumulate topic messages as new messages are produced to the topic, even when no consumer is attached to the durable subscription; this consumes resources on the JMS server and can eventually lead to resource issues such as quota exceptions, or even out-of-memory, because no consumer is ever removing messages from the durable subscription.

#### Exceptions

Exception Type | Condition
--- | ---
MessageException | if the session fails to create a subscriber due to some internal error.
InvalidDestinationException | if an invalid topic is specified.
InvalidSelectorException | if the message selector is invalid.

#### See Also

ISession Interface | WebLogic.Messaging Namespace | ISession. Overload List | Message selector syntax. | Deleting durable subscriptions.