Java tutorial
/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 1997-2013 Oracle and/or its affiliates. All rights reserved. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common Development * and Distribution License("CDDL") (collectively, 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/CDDL+GPL_1_1.html * or packager/legal/LICENSE.txt. See the License for the specific * language governing permissions and limitations under the License. * * When distributing the software, include this License Header Notice in each * file and include the License file at packager/legal/LICENSE.txt. * * GPL Classpath Exception: * Oracle designates this particular file as subject to the "Classpath" * exception as provided by Oracle in the GPL Version 2 section of the License * file that accompanied this code. * * Modifications: * If applicable, add the following below the License Header, with the fields * enclosed by brackets [] replaced by your own identifying information: * "Portions Copyright [year] [name of copyright owner]" * * Contributor(s): * If you wish your version of this file to be governed by only the CDDL or * only the GPL Version 2, indicate your decision by adding "[Contributor] * elects to include this software in this distribution under the [CDDL or GPL * Version 2] license." If you don't indicate a single choice of license, a * recipient has the option to distribute your version of this file under * either the CDDL, the GPL Version 2 or to extend the choice of license to * its licensees as provided above. However, if you add GPL Version 2 code * and therefore, elected the GPL Version 2 license, then the option applies * only if the new code is made subject to such option by the copyright * holder. */ package javax.jms; import java.util.Enumeration; /** A client uses a {@code QueueBrowser} object to look at messages on a * queue without removing them. * * <P>The {@code getEnumeration} method returns a * {@code 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. * * <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 message must not be returned by a {@code QueueBrowser} before its delivery time has been reached. * *<P>A {@code QueueBrowser} can be created from either a * {@code Session} or a {@code QueueSession}. * * @see javax.jms.Session#createBrowser * @see javax.jms.QueueSession#createBrowser * @see javax.jms.QueueReceiver * * @version JMS 2.0 * @since JMS 1.0 * */ public interface QueueBrowser extends AutoCloseable { /** 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}. * * <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; }