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}