org.springframework.web.reactive.result.method.annotation.ExpressionValueMethodArgumentResolver 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.web.reactive.result.method.annotation;
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.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.server.ServerWebExchange;
/**
* Resolves method arguments annotated with {@code @Value}.
*
* 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 {
/**
* Create a new {@link ExpressionValueMethodArgumentResolver} instance.
* @param factory a bean factory to use for resolving {@code ${...}}
* placeholder and {@code #{...}} 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(@Nullable ConfigurableBeanFactory factory,
ReactiveAdapterRegistry registry) {
super(factory, registry);
}
@Override
public boolean supportsParameter(MethodParameter param) {
return checkAnnotatedParamNoReactiveWrapper(param, Value.class, (ann, type) -> true);
}
@Override
protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
Value ann = parameter.getParameterAnnotation(Value.class);
Assert.state(ann != null, "No Value annotation");
return new ExpressionValueNamedValueInfo(ann);
}
@Override
protected Object resolveNamedValue(String name, MethodParameter parameter, ServerWebExchange exchange) {
// No name to resolve
return null;
}
@Override
protected void handleMissingValue(String name, MethodParameter parameter) {
throw new UnsupportedOperationException("@Value is never required: " + parameter.getMethod());
}
private static final class ExpressionValueNamedValueInfo extends NamedValueInfo {
private ExpressionValueNamedValueInfo(Value annotation) {
super("@Value", false, annotation.value());
}
}
}