Merge pull request #23146 from otaconix

* pr/23146:
  Polish 'Support nested @PropertyMapping annotations'
  Support nested @PropertyMapping annotations

Closes gh-23146

spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/AnnotationsPropertySource.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -73,10 +73,10 @@ public class AnnotationsPropertySource extends EnumerablePropertySource<Class<?>
 		return properties;
 	}
 
-	private void collectProperties(String prefix, SkipPropertyMapping defaultSkip, MergedAnnotation<?> annotation,
+	private void collectProperties(String prefix, SkipPropertyMapping skip, MergedAnnotation<?> annotation,
 			Method attribute, Map<String, Object> properties) {
 		MergedAnnotation<?> attributeMapping = MergedAnnotations.from(attribute).get(PropertyMapping.class);
-		SkipPropertyMapping skip = attributeMapping.getValue("skip", SkipPropertyMapping.class).orElse(defaultSkip);
+		skip = attributeMapping.getValue("skip", SkipPropertyMapping.class).orElse(skip);
 		if (skip == SkipPropertyMapping.YES) {
 			return;
 		}
@@ -90,7 +90,7 @@ public class AnnotationsPropertySource extends EnumerablePropertySource<Class<?>
 			}
 		}
 		String name = getName(prefix, attributeMapping, attribute);
-		putProperties(name, value.get(), properties);
+		putProperties(name, skip, value.get(), properties);
 	}
 
 	private String getName(String prefix, MergedAnnotation<?> attributeMapping, Method attribute) {
@@ -118,11 +118,18 @@ public class AnnotationsPropertySource extends EnumerablePropertySource<Class<?>
 		return postfix;
 	}
 
-	private void putProperties(String name, Object value, Map<String, Object> properties) {
+	private void putProperties(String name, SkipPropertyMapping defaultSkip, Object value,
+			Map<String, Object> properties) {
 		if (ObjectUtils.isArray(value)) {
 			Object[] array = ObjectUtils.toObjectArray(value);
 			for (int i = 0; i < array.length; i++) {
-				properties.put(name + "[" + i + "]", array[i]);
+				putProperties(name + "[" + i + "]", defaultSkip, array[i], properties);
+			}
+		}
+		else if (value instanceof MergedAnnotation<?>) {
+			MergedAnnotation<?> annotation = (MergedAnnotation<?>) value;
+			for (Method attribute : annotation.getType().getDeclaredMethods()) {
+				collectProperties(name, defaultSkip, (MergedAnnotation<?>) value, attribute, properties);
 			}
 		}
 		else {

spring-boot-project/spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/properties/AnnotationsPropertySourceTests.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -21,6 +21,9 @@ import java.lang.annotation.RetentionPolicy;
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.boot.test.autoconfigure.properties.AnnotationsPropertySourceTests.DeeplyNestedAnnotations.Level1;
+import org.springframework.boot.test.autoconfigure.properties.AnnotationsPropertySourceTests.DeeplyNestedAnnotations.Level2;
+import org.springframework.boot.test.autoconfigure.properties.AnnotationsPropertySourceTests.NestedAnnotations.Entry;
 import org.springframework.core.annotation.AliasFor;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -172,6 +175,26 @@ class AnnotationsPropertySourceTests {
 		assertThat(source.containsProperty("testenum.value")).isFalse();
 	}
 
+	@Test
+	void nestedAnnotationsMapped() {
+		AnnotationsPropertySource source = new AnnotationsPropertySource(PropertyMappedWithNestedAnnotations.class);
+		assertThat(source.getProperty("testnested")).isNull();
+		assertThat(source.getProperty("testnested.entries[0]")).isNull();
+		assertThat(source.getProperty("testnested.entries[0].value")).isEqualTo("one");
+		assertThat(source.getProperty("testnested.entries[1]")).isNull();
+		assertThat(source.getProperty("testnested.entries[1].value")).isEqualTo("two");
+	}
+
+	@Test
+	void deeplyNestedAnnotationsMapped() {
+		AnnotationsPropertySource source = new AnnotationsPropertySource(
+				PropertyMappedWithDeeplyNestedAnnotations.class);
+		assertThat(source.getProperty("testdeeplynested")).isNull();
+		assertThat(source.getProperty("testdeeplynested.level1")).isNull();
+		assertThat(source.getProperty("testdeeplynested.level1.level2")).isNull();
+		assertThat(source.getProperty("testdeeplynested.level1.level2.value")).isEqualTo("level2");
+	}
+
 	static class NoAnnotation {
 
 	}
@@ -396,4 +419,51 @@ class AnnotationsPropertySourceTests {
 
 	}
 
+	@Retention(RetentionPolicy.RUNTIME)
+	@PropertyMapping("testnested")
+	@interface NestedAnnotations {
+
+		Entry[] entries();
+
+		@Retention(RetentionPolicy.RUNTIME)
+		@interface Entry {
+
+			String value();
+
+		}
+
+	}
+
+	@NestedAnnotations(entries = { @Entry("one"), @Entry("two") })
+	static class PropertyMappedWithNestedAnnotations {
+
+	}
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@PropertyMapping("testdeeplynested")
+	@interface DeeplyNestedAnnotations {
+
+		Level1 level1();
+
+		@Retention(RetentionPolicy.RUNTIME)
+		@interface Level1 {
+
+			Level2 level2();
+
+		}
+
+		@Retention(RetentionPolicy.RUNTIME)
+		@interface Level2 {
+
+			String value();
+
+		}
+
+	}
+
+	@DeeplyNestedAnnotations(level1 = @Level1(level2 = @Level2("level2")))
+	static class PropertyMappedWithDeeplyNestedAnnotations {
+
+	}
+
 }