001/*
002 * Copyright 2002-2019 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.handler.annotation.support;
018
019import java.util.Map;
020
021import org.springframework.core.MethodParameter;
022import org.springframework.core.convert.ConversionService;
023import org.springframework.lang.Nullable;
024import org.springframework.messaging.Message;
025import org.springframework.messaging.MessageHandlingException;
026import org.springframework.messaging.MessageHeaders;
027import org.springframework.messaging.handler.annotation.DestinationVariable;
028import org.springframework.messaging.handler.annotation.ValueConstants;
029import org.springframework.util.Assert;
030
031/**
032 * Resolve for {@link DestinationVariable @DestinationVariable} method parameters.
033 *
034 * @author Brian Clozel
035 * @since 4.0
036 */
037public class DestinationVariableMethodArgumentResolver extends AbstractNamedValueMethodArgumentResolver {
038
039        /** The name of the header used to for template variables. */
040        public static final String DESTINATION_TEMPLATE_VARIABLES_HEADER =
041                        DestinationVariableMethodArgumentResolver.class.getSimpleName() + ".templateVariables";
042
043
044        public DestinationVariableMethodArgumentResolver(ConversionService conversionService) {
045                super(conversionService, null);
046        }
047
048
049        @Override
050        public boolean supportsParameter(MethodParameter parameter) {
051                return parameter.hasParameterAnnotation(DestinationVariable.class);
052        }
053
054        @Override
055        protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
056                DestinationVariable annot = parameter.getParameterAnnotation(DestinationVariable.class);
057                Assert.state(annot != null, "No DestinationVariable annotation");
058                return new DestinationVariableNamedValueInfo(annot);
059        }
060
061        @Override
062        @Nullable
063        @SuppressWarnings("unchecked")
064        protected Object resolveArgumentInternal(MethodParameter parameter, Message<?> message, String name) {
065                MessageHeaders headers = message.getHeaders();
066                Map<String, String> vars = (Map<String, String>) headers.get(DESTINATION_TEMPLATE_VARIABLES_HEADER);
067                return vars != null ? vars.get(name) : null;
068        }
069
070        @Override
071        protected void handleMissingValue(String name, MethodParameter parameter, Message<?> message) {
072                throw new MessageHandlingException(message, "Missing path template variable '" + name + "' " +
073                                "for method parameter type [" + parameter.getParameterType() + "]");
074        }
075
076
077        private static final class DestinationVariableNamedValueInfo extends NamedValueInfo {
078
079                private DestinationVariableNamedValueInfo(DestinationVariable annotation) {
080                        super(annotation.value(), true, ValueConstants.DEFAULT_NONE);
081                }
082        }
083
084}