Merge 9034e73bd2 into 7e6874ad80

Closes gh-35580

framework-docs/modules/ROOT/pages/core/beans/annotation-config/autowired.adoc

@@ -37,18 +37,18 @@ Kotlin::
 ----
 ======
 
-[NOTE]
+[TIP]
 ====
-As of Spring Framework 4.3, an `@Autowired` annotation on such a constructor is no longer
-necessary if the target bean defines only one constructor to begin with. However, if
-several constructors are available and there is no primary/default constructor, at least
-one of the constructors must be annotated with `@Autowired` in order to instruct the
-container which one to use. See the discussion on
-xref:core/beans/annotation-config/autowired.adoc#beans-autowired-annotation-constructor-resolution[constructor resolution] for details.
+An `@Autowired` annotation on such a constructor is not necessary if the target bean
+defines only one constructor. However, if several constructors are available and there is
+no primary or default constructor, at least one of the constructors must be annotated
+with `@Autowired` in order to instruct the container which one to use. See the discussion
+on xref:core/beans/annotation-config/autowired.adoc#beans-autowired-annotation-constructor-resolution[constructor resolution]
+for details.
 ====
 
-You can also apply the `@Autowired` annotation to _traditional_ setter methods,
-as the following example shows:
+You can apply the `@Autowired` annotation to _traditional_ setter methods, as the
+following example shows:
 
 [tabs]
 ======
@@ -84,8 +84,8 @@ Kotlin::
 ----
 ======
 
-You can also apply the annotation to methods with arbitrary names and multiple
-arguments, as the following example shows:
+You can apply `@Autowired` to methods with arbitrary names and multiple arguments, as the
+following example shows:
 
 [tabs]
 ======
@@ -176,14 +176,15 @@ Kotlin::
 ====
 Make sure that your target components (for example, `MovieCatalog` or `CustomerPreferenceDao`)
 are consistently declared by the type that you use for your `@Autowired`-annotated
-injection points. Otherwise, injection may fail due to a "no type match found" error at runtime.
+injection points. Otherwise, injection may fail due to a "no type match found" error at
+runtime.
 
 For XML-defined beans or component classes found via classpath scanning, the container
 usually knows the concrete type up front. However, for `@Bean` factory methods, you need
 to make sure that the declared return type is sufficiently expressive. For components
 that implement several interfaces or for components potentially referred to by their
-implementation type, consider declaring the most specific return type on your factory
-method (at least as specific as required by the injection points referring to your bean).
+implementation type, declare the most specific return type on your factory method (at
+least as specific as required by the injection points referring to your bean).
 ====
 
 .[[beans-autowired-annotation-self-injection]]Self Injection
@@ -312,8 +313,8 @@ through `@Order` values in combination with `@Primary` on a single bean for each
 ====
 
 Even typed `Map` instances can be autowired as long as the expected key type is `String`.
-The map values contain all beans of the expected type, and the keys contain the
-corresponding bean names, as the following example shows:
+The map values are all beans of the expected type, and the keys are the corresponding
+bean names, as the following example shows:
 
 [tabs]
 ======
@@ -431,7 +432,7 @@ annotated constructor does not have to be public.
 ====
 
 Alternatively, you can express the non-required nature of a particular dependency
-through Java 8's `java.util.Optional`, as the following example shows:
+through Java's `java.util.Optional`, as the following example shows:
 
 [source,java,indent=0,subs="verbatim,quotes"]
 ----
@@ -445,8 +446,8 @@ through Java 8's `java.util.Optional`, as the following example shows:
 ----
 
 You can also use a parameter-level `@Nullable` annotation (of any kind in any package --
-for example, `javax.annotation.Nullable` from JSR-305) or just leverage Kotlin built-in
-null-safety support:
+for example, `org.jspecify.annotations.Nullable` from JSpecify) or just leverage Kotlin's
+built-in null-safety support:
 
 [tabs]
 ======
@@ -477,13 +478,6 @@ Kotlin::
 ----
 ======
 
-[NOTE]
-====
-A type-level `@Nullable` annotation such as from JSpecify is not supported in Spring
-Framework 6.2 yet. You need to upgrade to Spring Framework 7.0 where the framework
-detects type-level annotations and consistently declares JSpecify in its own codebase.
-====
-
 You can also use `@Autowired` for interfaces that are well-known resolvable
 dependencies: `BeanFactory`, `ApplicationContext`, `Environment`, `ResourceLoader`,
 `ApplicationEventPublisher`, and `MessageSource`. These interfaces and their extended
@@ -528,5 +522,6 @@ class MovieRecommender {
 The `@Autowired`, `@Inject`, `@Value`, and `@Resource` annotations are handled by Spring
 `BeanPostProcessor` implementations. This means that you cannot apply these annotations
 within your own `BeanPostProcessor` or `BeanFactoryPostProcessor` types (if any).
+
 These types must be 'wired up' explicitly by using XML or a Spring `@Bean` method.
 ====

spring-core/src/main/java/org/springframework/core/convert/support/ConversionUtils.java

@@ -21,8 +21,9 @@ import org.jspecify.annotations.Nullable;
 import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.core.convert.converter.ConditionalConverter;
+import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.converter.GenericConverter;
-import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
 /**
@@ -71,13 +72,30 @@ abstract class ConversionUtils {
 		return false;
 	}
 
-	public static Class<?> getEnumType(Class<?> targetType) {
+	public static @Nullable Class<?> getEnumType(Class<?> targetType) {
 		Class<?> enumType = targetType;
 		while (enumType != null && !enumType.isEnum()) {
 			enumType = enumType.getSuperclass();
 		}
-		Assert.notNull(enumType, () -> "The target type " + targetType.getName() + " does not refer to an enum");
 		return enumType;
 	}
 
+	static class NonConvertableToEnum<T> implements Converter<String, T>, ConditionalConverter {
+
+		private final Class<T> targetType;
+
+		public NonConvertableToEnum(Class<T> targetType) {
+			this.targetType = targetType;
+		}
+
+		@Override
+		public boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType) {
+			return false;
+		}
+
+		@Override
+		public @Nullable T convert(String source) {
+			throw new IllegalArgumentException("The target type " + targetType.getName() + " does not refer to an enum");
+		}
+	}
 }

spring-core/src/main/java/org/springframework/core/convert/support/IntegerToEnumConverterFactory.java

@@ -31,7 +31,11 @@ final class IntegerToEnumConverterFactory implements ConverterFactory<Integer, E
 
 	@Override
 	public <T extends Enum> Converter<Integer, T> getConverter(Class<T> targetType) {
-		return new IntegerToEnum(ConversionUtils.getEnumType(targetType));
+		Class<?> enumType = ConversionUtils.getEnumType(targetType);
+		if (enumType == null) {
+			return new ConversionUtils.NonConvertableToEnum(targetType);
+		}
+		return new IntegerToEnum(enumType);
 	}
 
 

spring-core/src/main/java/org/springframework/core/convert/support/StringToEnumConverterFactory.java

@@ -33,9 +33,12 @@ final class StringToEnumConverterFactory implements ConverterFactory<String, Enu
 
 	@Override
 	public <T extends Enum> Converter<String, T> getConverter(Class<T> targetType) {
-		return new StringToEnum(ConversionUtils.getEnumType(targetType));
+		Class<?> enumType = ConversionUtils.getEnumType(targetType);
+		if (enumType == null) {
+			return new ConversionUtils.NonConvertableToEnum(targetType);
+		}
+		return new StringToEnum(enumType);
 	}
-
 
 	private static class StringToEnum<T extends Enum> implements Converter<String, T> {
 

spring-core/src/test/java/org/springframework/core/convert/support/GenericConversionServiceTests.java

@@ -503,6 +503,16 @@ class GenericConversionServiceTests {
 		assertThat(conversionService.convert("base1", MyEnum.class)).isEqualTo(MyEnum.A);
 	}
 
+	@Test
+	void toEnumCanConvertShouldNotThrowException() {
+		conversionService.addConverterFactory(new IntegerToEnumConverterFactory());
+		conversionService.addConverterFactory(new StringToEnumConverterFactory());
+		assertThat(conversionService.canConvert(Integer.class, Enum.class)).isFalse();
+		assertThat(conversionService.canConvert(Integer.class, MyEnum.class)).isTrue();
+		assertThat(conversionService.canConvert(String.class, Enum.class)).isFalse();
+		assertThat(conversionService.canConvert(String.class, MyEnum.class)).isTrue();
+	}
+
 	@Test
 	void convertNullAnnotatedStringToString() throws Exception {
 		String source = null;