QueueBrowser.java

/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the License).  You may not use this file except in
 * compliance with the License.
 *
 * You can obtain a copy of the license at
 * https://glassfish.dev.java.net/public/CDDLv1.0.html or
 * glassfish/bootstrap/legal/CDDLv1.0.txt.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * Header Notice in each file and include the License file
 * at glassfish/bootstrap/legal/CDDLv1.0.txt.
 * If applicable, add the following below the CDDL Header,
 * with the fields enclosed by brackets [] replaced by
 * you own identifying information:
 * "Portions Copyrighted [year] [name of copyright owner]"
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 */

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;
}