Refine unmapped property support

Replace `@UnmappedPropertyValue` with a `skip` attribute on
`@PropertyMapping` so that any default attribute value can be skipped.

Closes gh-6455

Author: philwebb

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

@@ -17,7 +17,6 @@
 package org.springframework.boot.test.autoconfigure.properties;
 
 import java.lang.annotation.Annotation;
-import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -110,33 +109,32 @@ private void collectProperties(Annotation annotation, Method attribute,
 			PropertyMapping typeMapping, Map<String, Object> properties) {
 		PropertyMapping attributeMapping = AnnotationUtils.getAnnotation(attribute,
 				PropertyMapping.class);
-		if (isMapped(typeMapping, attributeMapping)) {
-			String name = getName(typeMapping, attributeMapping, attribute);
-			ReflectionUtils.makeAccessible(attribute);
-			Object value = ReflectionUtils.invokeMethod(attribute, annotation);
-			if (isValueMapped(value)) {
-				putProperties(name, value, properties);
+		SkipPropertyMapping skip = getMappingType(typeMapping, attributeMapping);
+		if (skip == SkipPropertyMapping.YES) {
+			return;
+		}
+		String name = getName(typeMapping, attributeMapping, attribute);
+		ReflectionUtils.makeAccessible(attribute);
+		Object value = ReflectionUtils.invokeMethod(attribute, annotation);
+		if (skip == SkipPropertyMapping.ON_DEFAULT_VALUE) {
+			Object defaultValue = AnnotationUtils.getDefaultValue(annotation,
+					attribute.getName());
+			if (ObjectUtils.nullSafeEquals(value, defaultValue)) {
+				return;
 			}
 		}
+		putProperties(name, value, properties);
 	}
 
-	private boolean isMapped(PropertyMapping typeMapping,
+	private SkipPropertyMapping getMappingType(PropertyMapping typeMapping,
 			PropertyMapping attributeMapping) {
 		if (attributeMapping != null) {
-			return attributeMapping.map();
+			return attributeMapping.skip();
 		}
-		return (typeMapping != null && typeMapping.map());
-	}
-
-	private boolean isValueMapped(Object value) {
-		if (value != null && value instanceof Enum) {
-			Field field = ReflectionUtils.findField(value.getClass(),
-					((Enum<?>) value).name());
-			if (AnnotatedElementUtils.isAnnotated(field, UnmappedPropertyValue.class)) {
-				return false;
-			}
+		if (typeMapping != null) {
+			return typeMapping.skip();
 		}
-		return true;
+		return SkipPropertyMapping.YES;
 	}
 
 	private String getName(PropertyMapping typeMapping, PropertyMapping attributeMapping,

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

@@ -47,7 +47,6 @@
  * @author Phillip Webb
  * @since 1.4.0
  * @see AnnotationsPropertySource
- * @see UnmappedPropertyValue
  * @see TestPropertySource
  */
 @Documented
@@ -64,11 +63,11 @@
 	String value() default "";
 
 	/**
-	 * Determines if mapping should occur. When specified at the type-level indicates if
-	 * mapping should occur by default or not. When used at the attribute-level, overrides
-	 * the type-level default.
-	 * @return if mapping should occur
+	 * Determines if mapping should be skipped. When specified at the type-level indicates
+	 * if skipping should occur by default or not. When used at the attribute-level,
+	 * overrides the type-level default.
+	 * @return if mapping should be skipped
 	 */
-	boolean map() default true;
+	SkipPropertyMapping skip() default SkipPropertyMapping.NO;
 
 }

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/UnmappedPropertyValue.java renamed to spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/properties/SkipPropertyMapping.java

@@ -16,21 +16,27 @@
 
 package org.springframework.boot.test.autoconfigure.properties;
 
-import java.lang.annotation.ElementType;
-import java.lang.annotation.Retention;
-import java.lang.annotation.RetentionPolicy;
-import java.lang.annotation.Target;
-
 /**
- * Indicates that a single value should not be mapped when referenced from a
- * {@link PropertyMapping @PropertyMapping} annotation.
+ * Enum used to control when {@link PropertyMapping} is skipped.
  *
  * @author Phillip Webb
  * @since 1.4.0
- * @see PropertyMapping
  */
-@Retention(RetentionPolicy.RUNTIME)
-@Target({ ElementType.FIELD })
-public @interface UnmappedPropertyValue {
+public enum SkipPropertyMapping {
+
+	/**
+	 * Skip the mapping the property.
+	 */
+	YES,
+
+	/**
+	 * Skip mapping the property when the default attribute value is specified.
+	 */
+	ON_DEFAULT_VALUE,
+
+	/**
+	 * Don't skip mapping the property.
+	 */
+	NO,
 
 }

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/servlet/AutoConfigureMockMvc.java

@@ -27,6 +27,7 @@
 
 import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
 import org.springframework.boot.test.autoconfigure.properties.PropertyMapping;
+import org.springframework.boot.test.autoconfigure.properties.SkipPropertyMapping;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.MvcResult;
 
@@ -57,6 +58,7 @@
 	 * How {@link MvcResult} information should be printed after each MockMVC invocation.
 	 * @return how information is printed
 	 */
+	@PropertyMapping(skip = SkipPropertyMapping.ON_DEFAULT_VALUE)
 	MockMvcPrint print() default MockMvcPrint.DEFAULT;
 
 	/**

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/web/servlet/MockMvcPrint.java

@@ -16,8 +16,6 @@
 
 package org.springframework.boot.test.autoconfigure.web.servlet;
 
-import org.springframework.boot.test.autoconfigure.properties.UnmappedPropertyValue;
-
 /**
  * MVC print options specified from {@link AutoConfigureMockMvc}.
  *
@@ -30,7 +28,7 @@ public enum MockMvcPrint {
 	 * Use the default print setting ({@code MockMvcPrint.SYSTEM_OUT} unless explicitly
 	 * overridden).
 	 */
-	@UnmappedPropertyValue DEFAULT,
+	DEFAULT,
 
 	/**
 	 * Log MVC interactions at the {@code DEBUG} level.

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

@@ -262,7 +262,7 @@ static class NotMappedAtTypeLevel {
 	}
 
 	@Retention(RetentionPolicy.RUNTIME)
-	@PropertyMapping(map = false)
+	@PropertyMapping(skip = SkipPropertyMapping.YES)
 	static @interface NotMappedAtTypeLevelAnnotation {
 
 		@PropertyMapping
@@ -283,7 +283,7 @@ static class NotMappedAtAttributeLevel {
 
 		String value();
 
-		@PropertyMapping(map = false)
+		@PropertyMapping(skip = SkipPropertyMapping.YES)
 		String ignore() default "xyz";
 
 	}
@@ -362,7 +362,9 @@ static class PropertyMappedAttributeWithAnAlias {
 	static @interface AttributeWithAliasAnnotation {
 
 		@AliasFor(annotation = AliasedAttributeAnnotation.class, attribute = "value")
-		String value() default "foo";
+		String value()
+
+		default "foo";
 
 		String someOtherAttribute() default "shouldNotBeMapped";
 
@@ -410,13 +412,14 @@ static class EnumValueNotMapped {
 	@PropertyMapping("testenum")
 	static @interface EnumAnnotation {
 
-		EnumItem value();
+		@PropertyMapping(skip = SkipPropertyMapping.ON_DEFAULT_VALUE)
+		EnumItem value() default EnumItem.DEFAULT;
 
 	}
 
 	enum EnumItem {
 
-		@UnmappedPropertyValue DEFAULT,
+		DEFAULT,
 
 		ONE,