/*
* @(#)QueueBrowser.java 1.20 02/04/09
*
* Copyright 1997-2002 Sun Microsystems, Inc. All Rights Reserved.
*
* SUN PROPRIETARY/CONFIDENTIAL.
* This software is the proprietary information of Sun Microsystems, Inc.
* Use is subject to license terms.
*
*/
package javax.jms;
import java.util.Enumeration;
/** A client uses a <CODE>QueueBrowser</CODE> object to look at messages on a
* queue without removing them.
*
* <P>The <CODE>getEnumeration</CODE> method returns a
* <CODE>java.util.Enumeration</CODE> 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.
*
* <P>Messages may be arriving and expiring while the scan is done. The JMS 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.
*
*<P>A <CODE>QueueBrowser</CODE> can be created from either a
* <CODE>Session</CODE> or a <CODE> QueueSession</CODE>.
*
* @version 1.1 April 9, 2002
* @author Mark Hapner
* @author Rich Burridge
* @author Kate Stout
*
* @see javax.jms.Session#createBrowser
* @see javax.jms.QueueSession#createBrowser
* @see javax.jms.QueueReceiver
*/
public interface QueueBrowser {
/** Gets the queue associated with this queue browser.
*
* @return the queue
*
* @exception JMSException if the JMS provider fails to get the
* queue associated with this browser
* due to some internal error.
*/
Queue
getQueue() throws JMSException;
/** Gets this queue browser's message selector expression.
*
* @return 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)
*
* @exception JMSException if the JMS provider fails to get the
* message selector for this browser
* due to some internal error.
*/
String
getMessageSelector() throws JMSException;
/** Gets an enumeration for browsing the current queue messages in the
* order they would be received.
*
* @return an enumeration for browsing the messages
*
* @exception JMSException if the JMS provider fails to get the
* enumeration for this browser
* due to some internal error.
*/
Enumeration
getEnumeration() throws JMSException;
/** Closes the <CODE>QueueBrowser</CODE>.
*
* <P>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.
*
* @exception JMSException if the JMS provider fails to close this
* browser due to some internal error.
*/
void
close() throws JMSException;
}
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