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8323707: Adjust Classfile API's type arg model to better represent the embodied type

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Reviewed-by: asotona
This commit is contained in:
Chen Liang 2024-05-03 11:08:33 +00:00 • committed by Adam Sotona
parent f78fa0556d
commit c60474b122
6 changed files with 107 additions and 85 deletions
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99
src/java.base/share/classes/java/lang/classfile/Signature.java
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@ -185,88 +185,107 @@ public sealed interface Signature {
/**
* Models the type argument.
*
* @sealedGraph
* @since 22
*/
@PreviewFeature(feature = PreviewFeature.Feature.CLASSFILE_API)
public sealed interface TypeArg
permits SignaturesImpl.TypeArgImpl {
public sealed interface TypeArg {
/**
* Indicator for whether a wildcard has default bound, no bound,
* an upper bound, or a lower bound
*
* @since 22
* Models an unbounded type argument {@code *}.
* @since 23
*/
@PreviewFeature(feature = PreviewFeature.Feature.CLASSFILE_API)
public enum WildcardIndicator {
/**
* default bound wildcard (empty)
*/
DEFAULT,
/**
* unbounded indicator {@code *}
*/
UNBOUNDED,
/**
* upper-bounded indicator {@code +}
*/
EXTENDS,
/**
* lower-bounded indicator {@code -}
*/
SUPER;
public sealed interface Unbounded extends TypeArg permits SignaturesImpl.UnboundedTypeArgImpl {
}
/** {@return the wildcard indicator} */
WildcardIndicator wildcardIndicator();
/**
* Models a type argument with an explicit bound type.
* @since 23
*/
@PreviewFeature(feature = PreviewFeature.Feature.CLASSFILE_API)
public sealed interface Bounded extends TypeArg permits SignaturesImpl.TypeArgImpl {
/** {@return the signature of the type bound, if any} */
Optional<RefTypeSig> boundType();
/**
* Models a type argument's wildcard indicator.
* @since 23
*/
@PreviewFeature(feature = PreviewFeature.Feature.CLASSFILE_API)
public enum WildcardIndicator {
/**
* No wildcard (empty), an exact type. Also known as
* {@index invariant}.
*/
NONE,
/**
* Upper-bound indicator {@code +}. Also known as
* {@index covariant}.
*/
EXTENDS,
/**
* Lower-bound indicator {@code -}. Also known as
* {@index contravariant}.
*/
SUPER;
}
/** {@return the kind of wildcard} */
WildcardIndicator wildcardIndicator();
/** {@return the signature of the type bound} */
RefTypeSig boundType();
}
/**
* {@return a bounded type arg}
* @param boundType the bound
* @since 23
*/
public static TypeArg of(RefTypeSig boundType) {
public static TypeArg.Bounded of(RefTypeSig boundType) {
requireNonNull(boundType);
return of(WildcardIndicator.DEFAULT, Optional.of(boundType));
return bounded(Bounded.WildcardIndicator.NONE, boundType);
}
/**
* {@return an unbounded type arg}
* @since 23
*/
public static TypeArg unbounded() {
return of(WildcardIndicator.UNBOUNDED, Optional.empty());
public static TypeArg.Unbounded unbounded() {
return SignaturesImpl.UnboundedTypeArgImpl.INSTANCE;
}
/**
* {@return an upper-bounded type arg}
* @param boundType the upper bound
* @since 23
*/
public static TypeArg extendsOf(RefTypeSig boundType) {
public static TypeArg.Bounded extendsOf(RefTypeSig boundType) {
requireNonNull(boundType);
return of(WildcardIndicator.EXTENDS, Optional.of(boundType));
return bounded(Bounded.WildcardIndicator.EXTENDS, boundType);
}
/**
* {@return a lower-bounded type arg}
* @param boundType the lower bound
* @since 23
*/
public static TypeArg superOf(RefTypeSig boundType) {
public static TypeArg.Bounded superOf(RefTypeSig boundType) {
requireNonNull(boundType);
return of(WildcardIndicator.SUPER, Optional.of(boundType));
return bounded(Bounded.WildcardIndicator.SUPER, boundType);
}
/**
* {@return a bounded type arg}
* @param wildcard the wild card
* @param boundType optional bound type
* @since 23
*/
public static TypeArg of(WildcardIndicator wildcard, Optional<RefTypeSig> boundType) {
public static TypeArg.Bounded bounded(Bounded.WildcardIndicator wildcard, RefTypeSig boundType) {
requireNonNull(wildcard);
requireNonNull(boundType);
return new SignaturesImpl.TypeArgImpl(wildcard, boundType);
}
}