001/*
002 * Copyright 2002-2015 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.jms.listener.adapter;
018
019import javax.jms.Destination;
020import javax.jms.JMSException;
021import javax.jms.Session;
022
023import org.springframework.jms.support.destination.DestinationResolver;
024import org.springframework.util.Assert;
025
026/**
027 * Return type of any JMS listener method used to indicate the actual response
028 * destination alongside the response itself. Typically used when said destination
029 * needs to be computed at runtime.
030 *
031 * <p>The example below sends a response with the content of the {@code result}
032 * argument to the {@code queueOut Queue}:
033 *
034 * <pre class="code">
035 * package com.acme.foo;
036 *
037 * public class MyService {
038 *     &#064;JmsListener
039 *     public JmsResponse process(String msg) {
040 *         // process incoming message
041 *         return JmsResponse.forQueue(result, "queueOut");
042 *     }
043 * }</pre>
044 *
045 * If the destination does not need to be computed at runtime,
046 * {@link org.springframework.messaging.handler.annotation.SendTo @SendTo}
047 * is the recommended declarative approach.
048 *
049 * @author Stephane Nicoll
050 * @since 4.2
051 * @see org.springframework.jms.annotation.JmsListener
052 * @see org.springframework.messaging.handler.annotation.SendTo
053 * @param <T> the type of the response
054 */
055public class JmsResponse<T> {
056
057        private final T response;
058
059        private final Object destination;
060
061
062        /**
063         * Create a new instance
064         * @param response the content of the result
065         * @param destination the destination
066         */
067        protected JmsResponse(T response, Object destination) {
068                Assert.notNull(response, "Result must not be null");
069                this.response = response;
070                this.destination = destination;
071        }
072
073
074        /**
075         * Return the content of the response.
076         */
077        public T getResponse() {
078                return this.response;
079        }
080
081        /**
082         * Resolve the {@link Destination} to use for this instance. The {@link DestinationResolver}
083         * and {@link Session} can be used to resolve a destination at runtime.
084         * @param destinationResolver the destination resolver to use if necessary
085         * @param session the session to use, if necessary
086         * @return the {@link Destination} to use
087         * @throws JMSException if the DestinationResolver failed to resolve the destination
088         */
089        public Destination resolveDestination(DestinationResolver destinationResolver, Session session)
090                        throws JMSException {
091
092                if (this.destination instanceof Destination) {
093                        return (Destination) this.destination;
094                }
095                if (this.destination instanceof DestinationNameHolder) {
096                        DestinationNameHolder nameHolder = (DestinationNameHolder) this.destination;
097                        return destinationResolver.resolveDestinationName(session,
098                                        nameHolder.destinationName, nameHolder.pubSubDomain);
099                }
100                return null;
101        }
102
103        @Override
104        public String toString() {
105                return "JmsResponse [" + "response=" + this.response + ", destination=" + this.destination + ']';
106        }
107
108
109        /**
110         * Create a {@link JmsResponse} targeting the queue with the specified name.
111         */
112        public static <T> JmsResponse<T> forQueue(T result, String queueName) {
113                Assert.notNull(queueName, "Queue name must not be null");
114                return new JmsResponse<T>(result, new DestinationNameHolder(queueName, false));
115        }
116
117        /**
118         * Create a {@link JmsResponse} targeting the topic with the specified name.
119         */
120        public static <T> JmsResponse<T> forTopic(T result, String topicName) {
121                Assert.notNull(topicName, "Topic name must not be null");
122                return new JmsResponse<T>(result, new DestinationNameHolder(topicName, true));
123        }
124
125        /**
126         * Create a {@link JmsResponse} targeting the specified {@link Destination}.
127         */
128        public static <T> JmsResponse<T> forDestination(T result, Destination destination) {
129                Assert.notNull(destination, "Destination must not be null");
130                return new JmsResponse<T>(result, destination);
131        }
132
133
134        /**
135         * Internal class combining a destination name
136         * and its target destination type (queue or topic).
137         */
138        private static class DestinationNameHolder {
139
140                private final String destinationName;
141
142                private final boolean pubSubDomain;
143
144                public DestinationNameHolder(String destinationName, boolean pubSubDomain) {
145                        this.destinationName = destinationName;
146                        this.pubSubDomain = pubSubDomain;
147                }
148
149                @Override
150                public String toString() {
151                        return this.destinationName + "{" + "pubSubDomain=" + this.pubSubDomain + '}';
152                }
153        }
154
155}