DeliveryMode.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]"
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 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 */

package javax.jms;

/** The delivery modes supported by the JMS API are <CODE>PERSISTENT</CODE> and
 * <CODE>NON_PERSISTENT</CODE>.
 *
 * <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</CODE>
 * 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</CODE>
 * and if the destination has a sufficient message retention policy.
 *
 *
 *
 * @version     1.0 - 7 August 1998
 * @author      Mark Hapner
 * @author      Rich Burridge
 */

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</CODE> message to be lost is
    * not defined.
    *
    * <P>A JMS provider must deliver a <CODE>NON_PERSISTENT</CODE> 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</CODE> message to be lost.
    */

  static final int PERSISTENT = 2;
}