org.springframework.boot.context.properties.ConfigurationPropertiesBeanFactoryInitializationAotProcessor Maven / Gradle / Ivy

/*
 * Copyright 2012-2023 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
 *
 *      https://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.boot.context.properties;

import java.lang.reflect.Constructor;
import java.util.ArrayList;
import java.util.List;

import org.springframework.aot.generate.GenerationContext;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
import org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor;
import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.SmartInstantiationAwareBeanPostProcessor;
import org.springframework.boot.context.properties.bind.BindConstructorProvider;
import org.springframework.boot.context.properties.bind.BindMethod;
import org.springframework.boot.context.properties.bind.Bindable;
import org.springframework.boot.context.properties.bind.BindableRuntimeHintsRegistrar;
import org.springframework.util.ClassUtils;

/**
 * {@link BeanFactoryInitializationAotProcessor} that contributes runtime hints for
 * configuration properties-annotated beans.
 *
 * @author Stephane Nicoll
 * @author Christoph Strobl
 * @author Sebastien Deleuze
 * @author Andy Wilkinson
 */
class ConfigurationPropertiesBeanFactoryInitializationAotProcessor implements BeanFactoryInitializationAotProcessor {

	@Override
	public ConfigurationPropertiesReflectionHintsContribution processAheadOfTime(
			ConfigurableListableBeanFactory beanFactory) {
		beanFactory.addBeanPostProcessor(new BindConstructorAwareBeanPostProcessor(beanFactory));
		String[] beanNames = beanFactory.getBeanNamesForAnnotation(ConfigurationProperties.class);
		List> bindables = new ArrayList<>();
		for (String beanName : beanNames) {
			Class beanType = beanFactory.getType(beanName, false);
			if (beanType != null) {
				BindMethod bindMethod = beanFactory.containsBeanDefinition(beanName)
						? (BindMethod) beanFactory.getBeanDefinition(beanName).getAttribute(BindMethod.class.getName())
						: null;
				bindables.add(Bindable.of(ClassUtils.getUserClass(beanType))
					.withBindMethod((bindMethod != null) ? bindMethod : BindMethod.JAVA_BEAN));
			}
		}
		return (!bindables.isEmpty()) ? new ConfigurationPropertiesReflectionHintsContribution(bindables) : null;
	}

	/**
	 * {@link SmartInstantiationAwareBeanPostProcessor} implementation to work around
	 * framework's constructor resolver for immutable configuration properties.
	 * 
	 * Constructor binding supports multiple constructors as long as one is identified as
	 * the candidate for binding. Unfortunately, framework is not aware of such feature
	 * and attempts to resolve the autowired constructor to use.
	 */
	static class BindConstructorAwareBeanPostProcessor implements SmartInstantiationAwareBeanPostProcessor {

		private final ConfigurableListableBeanFactory beanFactory;

		BindConstructorAwareBeanPostProcessor(ConfigurableListableBeanFactory beanFactory) {
			this.beanFactory = beanFactory;
		}

		@Override
		public Constructor[] determineCandidateConstructors(Class beanClass, String beanName)
				throws BeansException {
			BindMethod bindMethod = BindMethodAttribute.get(this.beanFactory, beanName);
			if (bindMethod != null && bindMethod == BindMethod.VALUE_OBJECT) {
				Constructor bindConstructor = BindConstructorProvider.DEFAULT.getBindConstructor(beanClass, false);
				if (bindConstructor != null) {
					return new Constructor[] { bindConstructor };
				}
			}
			return null;
		}

	}

	static final class ConfigurationPropertiesReflectionHintsContribution
			implements BeanFactoryInitializationAotContribution {

		private final List> bindables;

		private ConfigurationPropertiesReflectionHintsContribution(List> bindables) {
			this.bindables = bindables;
		}

		@Override
		public void applyTo(GenerationContext generationContext,
				BeanFactoryInitializationCode beanFactoryInitializationCode) {
			BindableRuntimeHintsRegistrar.forBindables(this.bindables)
				.registerHints(generationContext.getRuntimeHints());
		}

		Iterable> getBindables() {
			return this.bindables;
		}

	}

}