org.springframework.messaging.handler.annotation.support.HeadersMethodArgumentResolver Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.messaging.handler.annotation.support;
import java.lang.reflect.Method;
import java.util.Map;
import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.handler.annotation.Headers;
import org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver;
import org.springframework.messaging.support.MessageHeaderAccessor;
import org.springframework.util.ReflectionUtils;
/**
* {@link HandlerMethodArgumentResolver} for header method parameters. Resolves the
* following method parameters:
*
* - Parameters assignable to {@link Map} annotated with {@link Headers @Headers}
*
- Parameters of type {@link MessageHeaders}
*
- Parameters assignable to {@link MessageHeaderAccessor}
*
*
* @author Rossen Stoyanchev
* @since 4.0
*/
public class HeadersMethodArgumentResolver implements HandlerMethodArgumentResolver {
@Override
public boolean supportsParameter(MethodParameter parameter) {
Class paramType = parameter.getParameterType();
return ((parameter.hasParameterAnnotation(Headers.class) && Map.class.isAssignableFrom(paramType)) ||
MessageHeaders.class == paramType || MessageHeaderAccessor.class.isAssignableFrom(paramType));
}
@Override
@Nullable
public Object resolveArgument(MethodParameter parameter, Message message) throws Exception {
Class paramType = parameter.getParameterType();
if (Map.class.isAssignableFrom(paramType)) {
return message.getHeaders();
}
else if (MessageHeaderAccessor.class == paramType) {
MessageHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, MessageHeaderAccessor.class);
return (accessor != null ? accessor : new MessageHeaderAccessor(message));
}
else if (MessageHeaderAccessor.class.isAssignableFrom(paramType)) {
MessageHeaderAccessor accessor = MessageHeaderAccessor.getAccessor(message, MessageHeaderAccessor.class);
if (accessor != null && paramType.isAssignableFrom(accessor.getClass())) {
return accessor;
}
else {
Method method = ReflectionUtils.findMethod(paramType, "wrap", Message.class);
if (method == null) {
throw new IllegalStateException(
"Cannot create accessor of type " + paramType + " for message " + message);
}
return ReflectionUtils.invokeMethod(method, null, message);
}
}
else {
throw new IllegalStateException(
"Unexpected method parameter type " + paramType + "in method " + parameter.getMethod() + ". "
+ "@Headers method arguments must be assignable to java.util.Map.");
}
}
}