Interface ClassEntry

All Superinterfaces:

LoadableConstantEntry, PoolEntry

public sealed interface ClassEntry
extends LoadableConstantEntry

Models a CONSTANT_Class_info structure, representing a reference type, in the constant pool of a class file.

The use of a ClassEntry is modeled by a ClassDesc that is not primitive. Conversions are through ConstantPoolBuilder.classEntry(ClassDesc) and asSymbol().

A ClassEntry is composite:

ClassEntry(Utf8Entry name)

where name represents:

• The internal form of a binary name (JVMS 4.2.1), if and only if this ClassEntry represents a class or interface, such as java/lang/String for the String class.
• A field descriptor string (JVMS 4.3.2) representing an array type, if and only if this ClassEntry represents an array type, such as [I for the int[] type, or [Ljava/lang/String; for the String[] type.

A field descriptor string for an array type can be distinguished by its leading '[' character.

API Note:

The internal form of a binary name, where all occurrences of . in the name are replaced by /, is informally known as an internal name. This concept also applies to package names in addition to class and interface names.

See Java Virtual Machine Specification:

4.4.1 The CONSTANT_Class_info Structure

Since:

24

See Also:

• ConstantPoolBuilder::classEntry
• ClassDesc

Field Summary

Fields declared in interface PoolEntry

TAG_CLASS, TAG_DOUBLE, TAG_DYNAMIC, TAG_FIELDREF, TAG_FLOAT, TAG_INTEGER, TAG_INTERFACE_METHODREF, TAG_INVOKE_DYNAMIC, TAG_LONG, TAG_METHOD_HANDLE, TAG_METHOD_TYPE, TAG_METHODREF, TAG_MODULE, TAG_NAME_AND_TYPE, TAG_PACKAGE, TAG_STRING, TAG_UTF8

Modifier and Type	Field	Description
static final int	TAG_CLASS	The tag for CONSTANT_Class constant kind.
static final int	TAG_DOUBLE	The tag for CONSTANT_Double constant kind.
static final int	TAG_DYNAMIC	The tag for CONSTANT_Dynamic constant kind.
static final int	TAG_FIELDREF	The tag for CONSTANT_Fieldref constant kind.
static final int	TAG_FLOAT	The tag for CONSTANT_Float constant kind.
static final int	TAG_INTEGER	The tag for CONSTANT_Integer constant kind.
static final int	TAG_INTERFACE_METHODREF	The tag for CONSTANT_InterfaceMethodref constant kind.
static final int	TAG_INVOKE_DYNAMIC	The tag for CONSTANT_InvokeDynamic constant kind.
static final int	TAG_LONG	The tag for CONSTANT_Long constant kind.
static final int	TAG_METHOD_HANDLE	The tag for CONSTANT_MethodHandle constant kind.
static final int	TAG_METHOD_TYPE	The tag for CONSTANT_MethodType constant kind.
static final int	TAG_METHODREF	The tag for CONSTANT_Methodref constant kind.
static final int	TAG_MODULE	The tag for CONSTANT_Module constant kind.
static final int	TAG_NAME_AND_TYPE	The tag for CONSTANT_NameAndType constant kind.
static final int	TAG_PACKAGE	The tag for CONSTANT_Package constant kind.
static final int	TAG_STRING	The tag for CONSTANT_String constant kind.
static final int	TAG_UTF8	The tag for CONSTANT_Utf8 constant kind.

Method Summary

Modifier and Type	Method	Description
String	asInternalName()	Returns the represented reference type, as the internal form of a binary name or an array descriptor string.
ClassDesc	asSymbol()	Returns the represented reference type, as a symbolic descriptor.
default ConstantDesc	constantValue()	Returns a symbolic descriptor of this constant.
boolean	matches(ClassDesc desc)	Returns whether this entry describes the given reference type.
Utf8Entry	name()	Returns the Utf8Entry referred by this structure.

Methods declared in interface LoadableConstantEntry

typeKind

Modifier and Type	Method	Description
default TypeKind	typeKind()	Returns the data type of this constant.

Methods declared in interface PoolEntry

constantPool, index, tag, width

Modifier and Type	Method	Description
ConstantPool	constantPool()	Returns the constant pool this entry is from.
int	index()	Returns the index within the constant pool corresponding to this entry.
int	tag()	Returns the constant pool tag that describes the type of this entry.
int	width()	Returns the number of constant pool slots this entry consumes.

Method Details

constantValue

default ConstantDesc constantValue()

Returns a symbolic descriptor of this constant.

This is equivalent to asSymbol().

Specified by:

constantValue in interface LoadableConstantEntry

Returns:

a symbolic descriptor of this constant

See Also:

• ConstantPoolBuilder.loadableConstantEntry(ConstantDesc)

name

Utf8Entry name()

Returns the Utf8Entry referred by this structure. If the value of the UTF8 starts with a [, this represents an array type and the value is a descriptor string; otherwise, this represents a class or interface and the value is the internal form of a binary name.

Returns:

the Utf8Entry referred by this structure

See Also:

• ConstantPoolBuilder::classEntry(Utf8Entry)

asInternalName

String asInternalName()

Returns the represented reference type, as the internal form of a binary name or an array descriptor string. This is a shortcut for name().stringValue().

Returns:

the represented reference type, as the internal form of a binary name or an array descriptor string

asSymbol

ClassDesc asSymbol()

Returns the represented reference type, as a symbolic descriptor. The returned descriptor is never primitive.

API Note:

If only symbol equivalence is desired, matches should be used. It requires reduced parsing and can improve class file reading performance.

Returns:

the represented reference type, as a symbolic descriptor

See Also:

• ConstantPoolBuilder::classEntry(ClassDesc)

matches

boolean matches(ClassDesc desc)

Returns whether this entry describes the given reference type. Returns false if desc is primitive.

Parameters:

desc - the reference type

Returns:

whether this entry describes the given reference type

Since:

25