Generate appropriate bean registration code for scoped proxies

Closes gh-28383

spring-aop/src/main/java/org/springframework/aop/scope/ScopedProxyBeanRegistrationContributionProvider.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2002-2022 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.aop.scope;
+
+import java.lang.reflect.Executable;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.aot.generator.CodeContribution;
+import org.springframework.aot.generator.DefaultCodeContribution;
+import org.springframework.aot.generator.ProtectedAccess.Options;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.config.ConfigurableBeanFactory;
+import org.springframework.beans.factory.generator.BeanFactoryContribution;
+import org.springframework.beans.factory.generator.BeanInstantiationGenerator;
+import org.springframework.beans.factory.generator.BeanRegistrationBeanFactoryContribution;
+import org.springframework.beans.factory.generator.BeanRegistrationContributionProvider;
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.javapoet.support.MultiStatement;
+import org.springframework.lang.Nullable;
+
+/**
+ * {@link BeanRegistrationContributionProvider} for {@link ScopedProxyFactoryBean}.
+ *
+ * @author Stephane Nicoll
+ */
+class ScopedProxyBeanRegistrationContributionProvider implements BeanRegistrationContributionProvider {
+
+	private static final Log logger = LogFactory.getLog(ScopedProxyBeanRegistrationContributionProvider.class);
+
+
+	private final ConfigurableBeanFactory beanFactory;
+
+	ScopedProxyBeanRegistrationContributionProvider(ConfigurableBeanFactory beanFactory) {
+		this.beanFactory = beanFactory;
+	}
+
+	@Nullable
+	@Override
+	public BeanFactoryContribution getContributionFor(String beanName, RootBeanDefinition beanDefinition) {
+		Class<?> beanType = beanDefinition.getResolvableType().toClass();
+		return (beanType.equals(ScopedProxyFactoryBean.class))
+				? createScopedProxyBeanFactoryContribution(beanName, beanDefinition) : null;
+	}
+
+	@Nullable
+	private BeanFactoryContribution createScopedProxyBeanFactoryContribution(String beanName, RootBeanDefinition beanDefinition) {
+		String targetBeanName = getTargetBeanName(beanDefinition);
+		BeanDefinition targetBeanDefinition = getTargetBeanDefinition(targetBeanName);
+		if (targetBeanDefinition == null) {
+			logger.warn("Could not handle " + ScopedProxyFactoryBean.class.getSimpleName() +
+					": no target bean definition found with name " + targetBeanName);
+			return null;
+		}
+		RootBeanDefinition processedBeanDefinition = new RootBeanDefinition(beanDefinition);
+		processedBeanDefinition.setTargetType(targetBeanDefinition.getResolvableType());
+		processedBeanDefinition.getPropertyValues().removePropertyValue("targetBeanName");
+		return new BeanRegistrationBeanFactoryContribution(beanName, processedBeanDefinition,
+				getBeanInstantiationGenerator(targetBeanName));
+	}
+
+	private BeanInstantiationGenerator getBeanInstantiationGenerator(String targetBeanName) {
+		return new BeanInstantiationGenerator() {
+
+			@Override
+			public Executable getInstanceCreator() {
+				return ScopedProxyFactoryBean.class.getDeclaredConstructors()[0];
+			}
+
+			@Override
+			public CodeContribution generateBeanInstantiation(RuntimeHints runtimeHints) {
+				CodeContribution codeContribution = new DefaultCodeContribution(runtimeHints);
+				codeContribution.protectedAccess().analyze(getInstanceCreator(), Options.defaults().build());
+				MultiStatement statements = new MultiStatement();
+				statements.addStatement("$T factory = new $T()", ScopedProxyFactoryBean.class, ScopedProxyFactoryBean.class);
+				statements.addStatement("factory.setTargetBeanName($S)", targetBeanName);
+				statements.addStatement("factory.setBeanFactory(beanFactory)");
+				statements.addStatement("return factory.getObject()");
+				codeContribution.statements().add(statements.toLambdaBody("() ->"));
+				return codeContribution;
+			}
+		};
+	}
+
+	@Nullable
+	private String getTargetBeanName(BeanDefinition beanDefinition) {
+		Object value = beanDefinition.getPropertyValues().get("targetBeanName");
+		return (value instanceof String targetBeanName) ? targetBeanName : null;
+	}
+
+	@Nullable
+	private BeanDefinition getTargetBeanDefinition(@Nullable String targetBeanName) {
+		if (targetBeanName != null && this.beanFactory.containsBean(targetBeanName)) {
+			return this.beanFactory.getMergedBeanDefinition(targetBeanName);
+		}
+		return null;
+	}
+
+}