Interface Utf8Entry

All Superinterfaces:

AnnotationConstantValueEntry, CharSequence, PoolEntry

public sealed interface Utf8Entry
extends CharSequence, AnnotationConstantValueEntry

Models a CONSTANT_UTF8_info constant, representing strings, in the constant pool of a class file. This describes strings in the Modified UTF-8 format.

The use of a Utf8Entry is represented by a String. Conversions are through ConstantPoolBuilder.utf8Entry(String) and stringValue().

Some uses of Utf8Entry represent field or method descriptor strings, symbolically represented as ClassDesc or MethodTypeDesc, depending on where a Utf8Entry appear. Entries representing such uses are created with ConstantPoolBuilder.utf8Entry(ClassDesc) and ConstantPoolBuilder.utf8Entry(MethodTypeDesc), and they can be converted to symbolic descriptors on a per-use-site basis, such as in AnnotationValue.OfClass.classSymbol() and MethodModel.methodTypeSymbol().

Unlike most constant pool entries, a UTF-8 entry is of flexible length: it is represented as an array structure, with an u2 for the data length in bytes, followed by that number of bytes of Modified UTF-8 data. It can represent at most 65535 bytes of data due to the physical restrictions of u2.

See Java Virtual Machine Specification:

4.4.7 The CONSTANT_Utf8_info Structure

Since:

24

See Also:

• Modified UTF-8

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
boolean	equalsString(String s)	Returns whether this entry describes the same string as the provided string.
boolean	isFieldType(ClassDesc desc)	Returns whether this entry describes the descriptor string of this field type.
boolean	isMethodType(MethodTypeDesc desc)	Returns whether this entry describes the descriptor string of this method type.
String	stringValue()	Returns the string value for this entry.

Methods declared in interface AnnotationConstantValueEntry

constantValue

Modifier and Type	Method	Description
ConstantDesc	constantValue()	Returns the constant value.

Methods declared in interface CharSequence

charAt, chars, codePoints, getChars, isEmpty, length, subSequence, toString

Modifier and Type	Method	Description
char	charAt(int index)	Returns the char value at the specified index.
default IntStream	chars()	Returns a stream of int zero-extending the char values from this sequence.
default IntStream	codePoints()	Returns a stream of code point values from this sequence.
default void	getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)	Copies characters from this sequence into the given destination array.
default boolean	isEmpty()	Returns true if this character sequence is empty.
int	length()	Returns the length of this character sequence.
CharSequence	subSequence(int start, int end)	Returns a CharSequence that is a subsequence of this sequence.
String	toString()	Returns a string containing the characters in this sequence in the same order as this sequence.

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

stringValue

String stringValue()

Returns the string value for this entry.

API Note:

A Utf8Entry can be used directly as a CharSequence if String functionalities are not strictly desired. If only string equivalence is desired, equalsString should be used. Reduction of string processing can significantly improve class file reading performance.

Returns:

the string value for this entry

See Also:

• ConstantPoolBuilder.utf8Entry(String)

equalsString

boolean equalsString(String s)

Returns whether this entry describes the same string as the provided string.

Parameters:

s - the string to compare to

Returns:

whether this entry describes the same string as the provided string

isFieldType

boolean isFieldType(ClassDesc desc)

Returns whether this entry describes the descriptor string of this field type.

Parameters:

desc - the field type

Returns:

whether this entry describes the descriptor string of this field type

Since:

25

isMethodType

boolean isMethodType(MethodTypeDesc desc)

Returns whether this entry describes the descriptor string of this method type.

Parameters:

desc - the method type

Returns:

whether this entry describes the descriptor string of this method type

Since:

25