Allow bean factory initialization to have a more flexible signature

This commit allows bean factory initialization to use a more flexible
signature than just consuming the DefaultListableBeanFactory. The
environment and the resource loader can now be specified if necessary.

See gh-29005

spring-beans/src/main/java/org/springframework/beans/factory/aot/BeanFactoryInitializationCode.java

@@ -24,6 +24,7 @@ import org.springframework.aot.generate.MethodReference;
  * perform bean factory initialization.
  *
  * @author Phillip Webb
+ * @author Stephane Nicoll
  * @since 6.0
  * @see BeanFactoryInitializationAotContribution
  */
@@ -41,10 +42,16 @@ public interface BeanFactoryInitializationCode {
 	GeneratedMethods getMethods();
 
 	/**
-	 * Add an initializer method call.
-	 * @param methodReference a reference to the initialize method to call. The
-	 * referenced method must have the same functional signature as
-	 * {@code Consumer<DefaultListableBeanFactory>}.
+	 * Add an initializer method call. An initializer can use a flexible signature,
+	 * using any of the following:
+	 * <ul>
+	 * <li>{@code DefaultListableBeanFactory}, or {@code ConfigurableListableBeanFactory}
+	 * to use the bean factory.</li>
+	 * <li>{@code ConfigurableEnvironment} or {@code Environment} to access the
+	 * environment.</li>
+	 * <li>{@code ResourceLoader} to load resources.</li>
+	 * </ul>
+	 * @param methodReference a reference to the initialize method to call.
 	 */
 	void addInitializer(MethodReference methodReference);
 

spring-context/src/main/java/org/springframework/context/aot/ApplicationContextInitializationCodeGenerator.java

@@ -18,6 +18,7 @@ package org.springframework.context.aot;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Function;
 
 import javax.lang.model.element.Modifier;
 
@@ -27,15 +28,22 @@ import org.springframework.aot.generate.GenerationContext;
 import org.springframework.aot.generate.MethodReference;
 import org.springframework.aot.generate.MethodReference.ArgumentCodeGenerator;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationCode;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.context.ApplicationContextInitializer;
 import org.springframework.context.annotation.ContextAnnotationAutowireCandidateResolver;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.Environment;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.javapoet.ClassName;
 import org.springframework.javapoet.CodeBlock;
 import org.springframework.javapoet.MethodSpec;
 import org.springframework.javapoet.ParameterizedTypeName;
+import org.springframework.javapoet.TypeName;
 import org.springframework.javapoet.TypeSpec;
+import org.springframework.lang.Nullable;
 
 /**
  * Internal code generator to create the {@link ApplicationContextInitializer}.
@@ -89,15 +97,15 @@ class ApplicationContextInitializationCodeGenerator implements BeanFactoryInitia
 				BEAN_FACTORY_VARIABLE, ContextAnnotationAutowireCandidateResolver.class);
 		code.addStatement("$L.setDependencyComparator($T.INSTANCE)",
 				BEAN_FACTORY_VARIABLE, AnnotationAwareOrderComparator.class);
-		ArgumentCodeGenerator argCodeGenerator = createInitializerMethodsArgumentCodeGenerator();
+		ArgumentCodeGenerator argCodeGenerator = createInitializerMethodArgumentCodeGenerator();
 		for (MethodReference initializer : this.initializers) {
 			code.addStatement(initializer.toInvokeCodeBlock(argCodeGenerator, this.generatedClass.getName()));
 		}
 		return code.build();
 	}
 
-	private ArgumentCodeGenerator createInitializerMethodsArgumentCodeGenerator() {
-		return ArgumentCodeGenerator.of(DefaultListableBeanFactory.class, BEAN_FACTORY_VARIABLE);
+	static ArgumentCodeGenerator createInitializerMethodArgumentCodeGenerator() {
+		return ArgumentCodeGenerator.from(new InitializerMethodArgumentCodeGenerator());
 	}
 
 	GeneratedClass getGeneratedClass() {
@@ -114,4 +122,30 @@ class ApplicationContextInitializationCodeGenerator implements BeanFactoryInitia
 		this.initializers.add(methodReference);
 	}
 
+	private static class InitializerMethodArgumentCodeGenerator implements Function<TypeName, CodeBlock> {
+
+		@Override
+		@Nullable
+		public CodeBlock apply(TypeName typeName) {
+			return (typeName instanceof ClassName className ? apply(className) : null);
+		}
+
+		@Nullable
+		private CodeBlock apply(ClassName className) {
+			String name = className.canonicalName();
+			if (name.equals(DefaultListableBeanFactory.class.getName())
+					|| name.equals(ConfigurableListableBeanFactory.class.getName())) {
+				return CodeBlock.of(BEAN_FACTORY_VARIABLE);
+			}
+			else if (name.equals(ConfigurableEnvironment.class.getName())
+					|| name.equals(Environment.class.getName())) {
+				return CodeBlock.of("$L.getConfigurableEnvironment()", APPLICATION_CONTEXT_VARIABLE);
+			}
+			else if (name.equals(ResourceLoader.class.getName())) {
+				return CodeBlock.of(APPLICATION_CONTEXT_VARIABLE);
+			}
+			return null;
+		}
+	}
+
 }

spring-context/src/test/java/org/springframework/context/aot/ApplicationContextInitializationCodeGeneratorTests.java

@@ -0,0 +1,77 @@
+/*
+ * 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.context.aot;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import org.springframework.aot.generate.MethodReference.ArgumentCodeGenerator;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.support.AbstractBeanFactory;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.Environment;
+import org.springframework.core.env.StandardEnvironment;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.javapoet.ClassName;
+import org.springframework.javapoet.CodeBlock;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ApplicationContextInitializationCodeGenerator}.
+ *
+ * @author Stephane Nicoll
+ */
+class ApplicationContextInitializationCodeGeneratorTests {
+
+	private static final ArgumentCodeGenerator argCodeGenerator = ApplicationContextInitializationCodeGenerator.
+			createInitializerMethodArgumentCodeGenerator();
+
+	@ParameterizedTest
+	@MethodSource("methodArguments")
+	void argumentsForSupportedTypesAreResolved(Class<?> target, String expectedArgument) {
+		CodeBlock code = CodeBlock.of(expectedArgument);
+		assertThat(argCodeGenerator.generateCode(ClassName.get(target))).isEqualTo(code);
+	}
+
+	@Test
+	void argumentForUnsupportedBeanFactoryIsNotResolved() {
+		assertThat(argCodeGenerator.generateCode(ClassName.get(AbstractBeanFactory.class))).isNull();
+	}
+
+	@Test
+	void argumentForUnsupportedEnvironmentIsNotResolved() {
+		assertThat(argCodeGenerator.generateCode(ClassName.get(StandardEnvironment.class))).isNull();
+	}
+
+	static Stream<Arguments> methodArguments() {
+		String applicationContext = "applicationContext";
+		String environment = applicationContext + ".getConfigurableEnvironment()";
+		return Stream.of(
+				Arguments.of(DefaultListableBeanFactory.class, "beanFactory"),
+				Arguments.of(ConfigurableListableBeanFactory.class, "beanFactory"),
+				Arguments.of(ConfigurableEnvironment.class, environment),
+				Arguments.of(Environment.class, environment),
+				Arguments.of(ResourceLoader.class, applicationContext));
+	}
+
+}