001/*
002 * Copyright 2002-2017 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.messaging.core;
018
019import org.springframework.beans.BeansException;
020import org.springframework.beans.factory.BeanFactory;
021import org.springframework.beans.factory.BeanFactoryAware;
022import org.springframework.lang.Nullable;
023import org.springframework.messaging.MessageChannel;
024import org.springframework.util.Assert;
025
026/**
027 * An implementation of {@link DestinationResolver} that interprets a destination
028 * name as the bean name of a {@link MessageChannel} and looks up the bean in
029 * the configured {@link BeanFactory}.
030 *
031 * @author Mark Fisher
032 * @since 4.0
033 */
034public class BeanFactoryMessageChannelDestinationResolver
035                implements DestinationResolver<MessageChannel>, BeanFactoryAware {
036
037        @Nullable
038        private BeanFactory beanFactory;
039
040
041        /**
042         * A default constructor that can be used when the resolver itself is configured
043         * as a Spring bean and will have the {@code BeanFactory} injected as a result
044         * of ing having implemented {@link BeanFactoryAware}.
045         */
046        public BeanFactoryMessageChannelDestinationResolver() {
047        }
048
049        /**
050         * A constructor that accepts a {@link BeanFactory} useful if instantiating this
051         * resolver manually rather than having it defined as a Spring-managed bean.
052         * @param beanFactory the bean factory to perform lookups against
053         */
054        public BeanFactoryMessageChannelDestinationResolver(BeanFactory beanFactory) {
055                Assert.notNull(beanFactory, "beanFactory must not be null");
056                this.beanFactory = beanFactory;
057        }
058
059
060        @Override
061        public void setBeanFactory(BeanFactory beanFactory) {
062                this.beanFactory = beanFactory;
063        }
064
065
066        @Override
067        public MessageChannel resolveDestination(String name) {
068                Assert.state(this.beanFactory != null, "No BeanFactory configured");
069                try {
070                        return this.beanFactory.getBean(name, MessageChannel.class);
071                }
072                catch (BeansException ex) {
073                        throw new DestinationResolutionException(
074                                        "Failed to find MessageChannel bean with name '" + name + "'", ex);
075                }
076        }
077
078}