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.simp.annotation.support;
018
019import java.security.Principal;
020import java.util.Optional;
021
022import org.springframework.core.MethodParameter;
023import org.springframework.messaging.Message;
024import org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver;
025import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
026
027/**
028 * Resolver for arguments of type {@link Principal}, including {@code Optional<Principal>}.
029 *
030 * @author Rossen Stoyanchev
031 * @since 4.0
032 */
033public class PrincipalMethodArgumentResolver implements HandlerMethodArgumentResolver {
034
035        @Override
036        public boolean supportsParameter(MethodParameter parameter) {
037                MethodParameter nestedParameter = parameter.nestedIfOptional();
038                Class<?> paramType = nestedParameter.getNestedParameterType();
039                return Principal.class.isAssignableFrom(paramType);
040        }
041
042        @Override
043        public Object resolveArgument(MethodParameter parameter, Message<?> message){
044                Principal user = SimpMessageHeaderAccessor.getUser(message.getHeaders());
045                return parameter.isOptional() ? Optional.ofNullable(user) : user;
046        }
047
048}