Module java.base

Package java.lang.classfile^PREVIEW

Interface ClassHierarchyResolver

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface ClassHierarchyResolver

ClassHierarchyResolver is a preview API of the Java platform.

Programs can only use ClassHierarchyResolver when preview features are enabled.

Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.

Provides class hierarchy information for generating correct stack maps during code building.

Since:

22

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	ClassHierarchyResolver.ClassHierarchyInfoPREVIEW	Preview. Information about a resolved class.

Method Summary

Modifier and Type	Method	Description
default ClassHierarchyResolverPREVIEW	cached()	Returns a ClassHierarchyResolver that caches class hierarchy information from this resolver.
default ClassHierarchyResolverPREVIEW	cached(Supplier<Map<ClassDesc,ClassHierarchyResolver.ClassHierarchyInfoPREVIEW>> cacheFactory)	Returns a ClassHierarchyResolver that caches class hierarchy information from this resolver.
static ClassHierarchyResolverPREVIEW	defaultResolver()	Returns the default instance of ClassHierarchyResolverPREVIEW that gets ClassHierarchyResolver.ClassHierarchyInfoPREVIEW from system class loader with reflection.
ClassHierarchyResolver.ClassHierarchyInfoPREVIEW	getClassInfo(ClassDesc classDesc)	Returns the ClassHierarchyResolver.ClassHierarchyInfoPREVIEW for a given class name, or null if the name is unknown to the resolver.
static ClassHierarchyResolverPREVIEW	of(Collection<ClassDesc> interfaces, Map<ClassDesc,ClassDesc> classToSuperClass)	Returns a ClassHierarchyResolverPREVIEW that extracts class hierarchy information from collections of class hierarchy metadata
static ClassHierarchyResolverPREVIEW	ofClassLoading(ClassLoader loader)	Returns a ClassHierarchyResolver that extracts class hierarchy information via the Reflection API with a ClassLoader.
static ClassHierarchyResolverPREVIEW	ofClassLoading(MethodHandles.Lookup lookup)	Returns a ClassHierarchyResolver that extracts class hierarchy information via the Reflection API with a Lookup.
static ClassHierarchyResolverPREVIEW	ofResourceParsing(ClassLoader loader)	Returns a ClassHierarchyResolverPREVIEW that extracts class hierarchy information from classfiles located by a class loader.
static ClassHierarchyResolverPREVIEW	ofResourceParsing(Function<ClassDesc,InputStream> classStreamResolver)	Returns a ClassHierarchyResolverPREVIEW that extracts class hierarchy information from classfiles located by a mapping function.
default ClassHierarchyResolverPREVIEW	orElse(ClassHierarchyResolverPREVIEW other)	Chains this ClassHierarchyResolverPREVIEW with another to be consulted if this resolver does not know about the specified class.

Method Details

defaultResolver

static ClassHierarchyResolverPREVIEW defaultResolver()

Returns the default instance of ClassHierarchyResolver^PREVIEW that gets ClassHierarchyResolver.ClassHierarchyInfo^PREVIEW from system class loader with reflection.

Returns:

the default instance of ClassHierarchyResolver^PREVIEW that gets ClassHierarchyResolver.ClassHierarchyInfo^PREVIEW from system class loader with reflection

getClassInfo

ClassHierarchyResolver.ClassHierarchyInfoPREVIEW getClassInfo(ClassDesc classDesc)

Returns the ClassHierarchyResolver.ClassHierarchyInfo^PREVIEW for a given class name, or null if the name is unknown to the resolver.

Parameters:

classDesc - descriptor of the class

Returns:

the ClassHierarchyResolver.ClassHierarchyInfo^PREVIEW for a given class name, or null if the name is unknown to the resolver

Throws:

IllegalArgumentException - if a class shouldn't be queried for hierarchy

orElse

default ClassHierarchyResolverPREVIEW orElse(ClassHierarchyResolverPREVIEW other)

Chains this ClassHierarchyResolver^PREVIEW with another to be consulted if this resolver does not know about the specified class.

Implementation Requirements:

The default implementation returns resolver implemented to ask other resolver in cases where this resolver returns null.

Parameters:

other - the other resolver

Returns:

the chained resolver

cached

default ClassHierarchyResolverPREVIEW cached(Supplier<Map<ClassDesc,ClassHierarchyResolver.ClassHierarchyInfoPREVIEW>> cacheFactory)

Returns a ClassHierarchyResolver that caches class hierarchy information from this resolver. The returned resolver will not update if delegate resolver returns differently. The thread safety of the returned resolver depends on the thread safety of the map returned by the cacheFactory.

Implementation Requirements:

The default implementation returns resolver holding an instance of the cache map provided by the cacheFactory. It asks the cache map always first and fills the cache map with all resolved and also unresolved class info. The cache map may refuse null keys and values.

Parameters:

cacheFactory - the factory for the cache

Returns:

the ClassHierarchyResolver with caching

cached

default ClassHierarchyResolverPREVIEW cached()

Returns a ClassHierarchyResolver that caches class hierarchy information from this resolver. The returned resolver will not update if delegate resolver returns differently. The returned resolver is not thread-safe.

MethodHandles.Lookup lookup = ...;
ClassHierarchyResolver resolver = ClassHierarchyResolver.ofClassLoading(lookup).cached();

Implementation Requirements:

The default implementation calls cached(Supplier) with HashMap supplier as cacheFactory.

Returns:

the ClassHierarchyResolver

ofResourceParsing

static ClassHierarchyResolverPREVIEW ofResourceParsing(Function<ClassDesc,InputStream> classStreamResolver)

Returns a ClassHierarchyResolver^PREVIEW that extracts class hierarchy information from classfiles located by a mapping function. The mapping function should return null if it cannot provide a mapping for a classfile. Any IOException from the provided input stream is rethrown as an UncheckedIOException.

Parameters:

classStreamResolver - maps class descriptors to classfile input streams

Returns:

the ClassHierarchyResolver^PREVIEW

ofResourceParsing

static ClassHierarchyResolverPREVIEW ofResourceParsing(ClassLoader loader)

Returns a ClassHierarchyResolver^PREVIEW that extracts class hierarchy information from classfiles located by a class loader.

Parameters:

loader - the class loader, to find class files

Returns:

the ClassHierarchyResolver^PREVIEW

of

static ClassHierarchyResolverPREVIEW of(Collection<ClassDesc> interfaces,
 Map<ClassDesc,ClassDesc> classToSuperClass)

Returns a ClassHierarchyResolver^PREVIEW that extracts class hierarchy information from collections of class hierarchy metadata

Parameters:

interfaces - a collection of classes known to be interfaces

classToSuperClass - a map from classes to their super classes

Returns:

the ClassHierarchyResolver^PREVIEW

ofClassLoading

static ClassHierarchyResolverPREVIEW ofClassLoading(ClassLoader loader)

Returns a ClassHierarchyResolver that extracts class hierarchy information via the Reflection API with a ClassLoader.

Parameters:

loader - the class loader

Returns:

the class hierarchy resolver

ofClassLoading

static ClassHierarchyResolverPREVIEW ofClassLoading(MethodHandles.Lookup lookup)

Returns a ClassHierarchyResolver that extracts class hierarchy information via the Reflection API with a Lookup. If the class resolved is inaccessible to the given lookup, it throws IllegalArgumentException instead of returning null.

Parameters:

lookup - the lookup, must be able to access classes to resolve

Returns:

the class hierarchy resolver