Allow NestedConfigurationProperty on getters

This commit adds support adding `@NestedConfigurationProperty` on a
getter.

See gh-38844

Author: jaredtbates

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/JavaBeanPropertyDescriptor.java

@@ -53,7 +53,8 @@ ExecutableElement getSetter() {
 
 	@Override
 	protected boolean isMarkedAsNested(MetadataGenerationEnvironment environment) {
-		return environment.getNestedConfigurationPropertyAnnotation(this.field) != null;
+		return environment.getNestedConfigurationPropertyAnnotation(this.field) != null
+				|| environment.getNestedConfigurationPropertyAnnotation(getGetter()) != null;
 	}
 
 	@Override

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/ConfigurationMetadataAnnotationProcessorTests.java

@@ -45,6 +45,7 @@
 import org.springframework.boot.configurationsample.specific.BoxingPojo;
 import org.springframework.boot.configurationsample.specific.BuilderPojo;
 import org.springframework.boot.configurationsample.specific.DeprecatedLessPreciseTypePojo;
+import org.springframework.boot.configurationsample.specific.DeprecatedSimplePojo;
 import org.springframework.boot.configurationsample.specific.DeprecatedUnrelatedMethodPojo;
 import org.springframework.boot.configurationsample.specific.DoubleRegistrationProperties;
 import org.springframework.boot.configurationsample.specific.EmptyDefaultValueProperties;
@@ -336,6 +337,9 @@ void innerClassProperties() {
 		assertThat(metadata).has(Metadata.withProperty("config.third.value"));
 		assertThat(metadata).has(Metadata.withProperty("config.fourth"));
 		assertThat(metadata).isNotEqualTo(Metadata.withGroup("config.fourth"));
+		assertThat(metadata)
+				.has(Metadata.withGroup("config.fifth").ofType(DeprecatedSimplePojo.class).fromSource(InnerClassProperties.class));
+		assertThat(metadata).has(Metadata.withProperty("config.fifth.value").withDeprecation());
 	}
 
 	@Test

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/NestedConfigurationProperty.java

@@ -30,7 +30,7 @@
  * @author Phillip Webb
  * @since 1.2.0
  */
-@Target({ ElementType.FIELD, ElementType.RECORD_COMPONENT })
+@Target({ ElementType.FIELD, ElementType.RECORD_COMPONENT, ElementType.METHOD })
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 public @interface NestedConfigurationProperty {

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/specific/DeprecatedSimplePojo.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2012-2019 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.configurationsample.specific;
+
+/**
+ * POJO for use with samples needing a deprecated value.
+ *
+ * @author Jared Bates
+ */
+public class DeprecatedSimplePojo {
+
+	private int value;
+
+	@Deprecated
+	public int getValue() {
+		return this.value;
+	}
+
+	public void setValue(int value) {
+		this.value = value;
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/specific/InnerClassProperties.java

@@ -36,6 +36,8 @@ public class InnerClassProperties {
 
 	private Fourth fourth;
 
+	private final DeprecatedSimplePojo fifth = new DeprecatedSimplePojo();
+
 	public Foo getFirst() {
 		return this.first;
 	}
@@ -60,6 +62,11 @@ public void setFourth(Fourth fourth) {
 		this.fourth = fourth;
 	}
 
+	@NestedConfigurationProperty
+	public DeprecatedSimplePojo getFifth() {
+		return this.fifth;
+	}
+
 	public static class Foo {
 
 		private String name;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/NestedConfigurationProperty.java

@@ -38,7 +38,7 @@
  * @author Phillip Webb
  * @since 1.2.0
  */
-@Target({ ElementType.FIELD, ElementType.RECORD_COMPONENT })
+@Target({ ElementType.FIELD, ElementType.RECORD_COMPONENT, ElementType.METHOD })
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Nested