/* * Copyright 2002-2017 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.web.reactive.result.method.annotation; import java.util.Optional; import org.springframework.beans.factory.annotation.Value; import org.springframework.beans.factory.config.ConfigurableBeanFactory; import org.springframework.core.MethodParameter; import org.springframework.core.ReactiveAdapterRegistry; import org.springframework.web.server.ServerWebExchange; /** * Resolves method arguments annotated with {@code @Value}. * * <p>An {@code @Value} does not have a name but gets resolved from the default * value string, which may contain ${...} placeholder or Spring Expression * Language #{...} expressions. * * @author Rossen Stoyanchev * @since 5.0 */ public class ExpressionValueMethodArgumentResolver extends AbstractNamedValueSyncArgumentResolver { /** * @param factory a bean factory to use for resolving ${...} * placeholder and #{...} SpEL expressions in default values; * or {@code null} if default values are not expected to contain expressions * @param registry for checking reactive type wrappers */ public ExpressionValueMethodArgumentResolver(ConfigurableBeanFactory factory, ReactiveAdapterRegistry registry) { super(factory, registry); } @Override public boolean supportsParameter(MethodParameter param) { return checkAnnotatedParamNoReactiveWrapper(param, Value.class, (annot, type) -> true); } @Override protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) { Value annotation = parameter.getParameterAnnotation(Value.class); return new ExpressionValueNamedValueInfo(annotation); } @Override protected Optional<Object> resolveNamedValue(String name, MethodParameter parameter, ServerWebExchange exchange) { // No name to resolve return Optional.empty(); } @Override protected void handleMissingValue(String name, MethodParameter parameter) { throw new UnsupportedOperationException("@Value is never required: " + parameter.getMethod()); } private static class ExpressionValueNamedValueInfo extends NamedValueInfo { private ExpressionValueNamedValueInfo(Value annotation) { super("@Value", false, annotation.value()); } } }