RFR: 8343251: Facelift for Type and AnnotatedType specifications [v7]

[Chen Liang]

On Thu, 5 Dec 2024 17:54:34 GMT, Chen Liang <liach at openjdk.org> wrote:

>> The Type and AnnotatedType hierarchies have been enigmatic to new users: users have no clue how to categorize arbitrary type objects, when it is safe to cast to more specific types, and the exact conditions for method contracts.
>> 
>> A manifest is [JDK-8306039](https://bugs.openjdk.org/browse/JDK-8306039), where people are massively confused by the conditions for `ParameterizedType::getOwnerType` to return `null`.
>> 
>> To fix these problems, I consulted the JLS, used some terms from there and added JLS links to make the definitions concise and accurate.
>> 
>> Here are some actions:
>> 1. Add section for hierarchy overview for both Type and AnnotatedType
>> 2. Specify the underlying type for different AnnotatedType subinterfaces
>> 3. Define "inner member class" for `getOwnerType`, and refer to it in `AnnotatedType::getAnnotatedOwnerType`.
>> 4. Improve the specification for `ParameterizedType::getActualTypeArguments` to note the existence of owner types; also for annotated version
>> 5. Minor improvements to `ParameterizedType::getRawType`
>> 6. Move the equals specification for `ParameterizedType` to the actual `equals` method.
>> 
>> ApiDiff: https://cr.openjdk.org/~liach/apidiff/types-facelift/java.base/java/lang/reflect/package-summary.html
>> Javadoc: https://cr.openjdk.org/~liach/javadoc/types-facelift/java.base/java/lang/reflect/package-summary.html
>> 
>> Please review the associated CSR as well.
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Problems with owner type, kevin suggestions

src/java.base/share/classes/java/lang/reflect/AnnotatedType.java line 90:

> 88:  * method returns a {@link Class}.
> 89:  * <p>
> 90:  * For example, an annotated use {@code @TB Outer. at TA Inner} has an annotation

... is such an instance, and ...

src/java.base/share/classes/java/lang/reflect/AnnotatedWildcardType.java line 39:

> 37:  * For example, an annotated use {@code @TA ? extends @TB Number} has an
> 38:  * annotation {@code @TA} and represents the wildcard type argument {@code ?
> 39:  * extends Number}.  Its lower bound is the annotated use {@code @TB Number}

"lower" -> "upper", similar for "no upper bound" below

src/java.base/share/classes/java/lang/reflect/ParameterizedType.java line 124:

> 122:      * class or interface declaration} and have equal {@linkplain
> 123:      * #getActualTypeArguments() type parameters}, including those from the
> 124:      * {@linkplain #getOwnerType() enclosing classes}.

... if they are non-static nested types. (etc.)

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PR Review Comment: https://git.openjdk.org/jdk/pull/19977#discussion_r1899044102
PR Review Comment: https://git.openjdk.org/jdk/pull/19977#discussion_r1899043987
PR Review Comment: https://git.openjdk.org/jdk/pull/19977#discussion_r1899044212