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; /** The delivery modes supported by the JMS API are {@code PERSISTENT} and * {@code NON_PERSISTENT}. * * <P>A client marks a message as persistent if it feels that the * application will have problems if the message is lost in transit. * A client marks a message as non-persistent if an occasional * lost message is tolerable. Clients use delivery mode to tell a * JMS provider how to balance message transport reliability with throughput. * * <P>Delivery mode covers only the transport of the message to its * destination. Retention of a message at the destination until * its receipt is acknowledged is not guaranteed by a {@code PERSISTENT} * delivery mode. Clients should assume that message retention * policies are set administratively. Message retention policy * governs the reliability of message delivery from destination * to message consumer. For example, if a client's message storage * space is exhausted, some messages may be dropped in accordance with * a site-specific message retention policy. * * <P>A message is guaranteed to be delivered once and only once * by a JMS provider if the delivery mode of the message is * {@code PERSISTENT} * and if the destination has a sufficient message retention policy. * * @version JMS 2.0 * @since JMS 1.0 */ public interface DeliveryMode { /** This is the lowest-overhead delivery mode because it does not require * that the message be logged to stable storage. The level of JMS provider * failure that causes a {@code NON_PERSISTENT} message to be lost is * not defined. * * <P>A JMS provider must deliver a {@code NON_PERSISTENT} message * with an * at-most-once guarantee. This means that it may lose the message, but it * must not deliver it twice. */ static final int NON_PERSISTENT = 1; /** This delivery mode instructs the JMS provider to log the message to stable * storage as part of the client's send operation. Only a hard media * failure should cause a {@code PERSISTENT} message to be lost. */ static final int PERSISTENT = 2; }