Module jakarta.messaging

Package jakarta.jms

Interface QueueBrowser

All Superinterfaces:

AutoCloseable

public interface QueueBrowser
extends AutoCloseable

A client uses a QueueBrowser object to look at messages on a queue without removing them.

The getEnumeration method returns a java.util.Enumeration that is used to scan the queue's messages. It may be an enumeration of the entire content of a queue, or it may contain only the messages matching a message selector.

Messages may be arriving and expiring while the scan is done. The Jakarta Messaging API does not require the content of an enumeration to be a static snapshot of queue content. Whether these changes are visible or not depends on the JMS provider.

A message must not be returned by a QueueBrowser before its delivery time has been reached.

A QueueBrowser can be created from either a Session or a QueueSession.

Since:

JMS 1.0

Version:

Jakarta Messaging 2.0

See Also:

• Session.createBrowser(jakarta.jms.Queue)
• QueueSession.createBrowser(jakarta.jms.Queue)
• QueueReceiver

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the QueueBrowser.
Enumeration	getEnumeration()	Gets an enumeration for browsing the current queue messages in the order they would be received.
String	getMessageSelector()	Gets this queue browser's message selector expression.
Queue	getQueue()	Gets the queue associated with this queue browser.

Method Details

getQueue

Queue getQueue()
        throws JMSException

Gets the queue associated with this queue browser.

Returns:

the queue

Throws:

JMSException - if the Jakarta Messaging provider fails to get the queue associated with this browser due to some internal error.

getMessageSelector

String getMessageSelector()
                   throws JMSException

Gets this queue browser's message selector expression.

Returns:

this queue browser's message selector, or null if no message selector exists for the message consumer (that is, if the message selector was not set or was set to null or the empty string)

Throws:

JMSException - if the Jakarta Messaging provider fails to get the message selector for this browser due to some internal error.

getEnumeration

Enumeration getEnumeration()
                    throws JMSException

Gets an enumeration for browsing the current queue messages in the order they would be received.

Returns:

an enumeration for browsing the messages

Throws:

JMSException - if the Jakarta Messaging provider fails to get the enumeration for this browser due to some internal error.

close

void close()
    throws JMSException

Closes the QueueBrowser.

Since a provider may allocate some resources on behalf of a QueueBrowser outside the Java virtual machine, clients should close them when they are not needed. Relying on garbage collection to eventually reclaim these resources may not be timely enough.

Specified by:

close in interface AutoCloseable

Throws:

JMSException - if the Jakarta Messaging provider fails to close this browser due to some internal error.