Interface ConstantInstruction

All Superinterfaces:

ClassFileElement, CodeElement, Instruction

All Known Subinterfaces:

ConstantInstruction.ArgumentConstantInstruction, ConstantInstruction.IntrinsicConstantInstruction, ConstantInstruction.LoadConstantInstruction

public sealed interface ConstantInstruction
extends Instruction
permits ConstantInstruction.IntrinsicConstantInstruction, ConstantInstruction.ArgumentConstantInstruction, ConstantInstruction.LoadConstantInstruction

Models a constant-load instruction in the code array of a Code attribute, including "intrinsic", "argument", and "load" constant instructions. Corresponding opcodes have a kind of Opcode.Kind.CONSTANT. Delivered as a CodeElement when traversing the elements of a CodeModel.

The loaded constant value is symbolically represented as a ConstantDesc:

ConstantInstruction(ConstantDesc constantValue)

Sealed Class Hierarchy Graph:

Since:

24

See Also:

• Opcode.Kind.CONSTANT
• CodeBuilder::loadConstant

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	ConstantInstruction.ArgumentConstantInstruction	Models an "argument constant" instruction, which encodes the constant value in the instruction directly.
static interface	ConstantInstruction.IntrinsicConstantInstruction	Models an "intrinsic constant" instruction, which encodes the constant value in its opcode.
static interface	ConstantInstruction.LoadConstantInstruction	Models a "load constant" instruction, which encodes the constant value in the constant pool.

Method Summary

Modifier and Type	Method	Description
ConstantDesc	constantValue()	Returns the constant value.
static ConstantInstruction.ArgumentConstantInstruction	ofArgument(Opcode op, int value)	Returns an argument constant instruction.
static ConstantInstruction.IntrinsicConstantInstruction	ofIntrinsic(Opcode op)	Returns an intrinsic constant instruction.
static ConstantInstruction.LoadConstantInstruction	ofLoad(Opcode op, LoadableConstantEntry constant)	Returns a load constant instruction.
TypeKind	typeKind()	Returns the computational type of the constant.

Methods declared in interface java.lang.classfile.Instruction

opcode, sizeInBytes

Method Details

constantValue

ConstantDesc constantValue()

Returns the constant value.

Returns:

the constant value

typeKind

TypeKind typeKind()

Returns the computational type of the constant. This is derived from the constantValue.

Returns:

the computational type of the constant

ofIntrinsic

static ConstantInstruction.IntrinsicConstantInstruction ofIntrinsic(Opcode op)

Returns an intrinsic constant instruction.

Parameters:

op - the opcode for the specific type of intrinsic constant instruction, which must be of kind Opcode.Kind.CONSTANT

Returns:

an intrinsic constant instruction

Throws:

IllegalArgumentException - if the opcode does not represent a constant with implicit value

ofArgument

static ConstantInstruction.ArgumentConstantInstruction ofArgument(Opcode op,
 int value)

Returns an argument constant instruction.

value must be in the range of byte, [-128, 127], for Opcode.BIPUSH, and in the range of short, [-32768, 32767], for Opcode.SIPUSH.

Parameters:

op - the opcode for the specific type of argument constant instruction, which must be Opcode.BIPUSH or Opcode.SIPUSH

value - the constant value

Returns:

an argument constant instruction

Throws:

IllegalArgumentException - if the opcode is not Opcode.BIPUSH or Opcode.SIPUSH, or if the constant value is out of range for the opcode

ofLoad

static ConstantInstruction.LoadConstantInstruction ofLoad(Opcode op,
 LoadableConstantEntry constant)

Returns a load constant instruction.

Parameters:

op - the opcode for the specific type of load constant instruction, which must be of kind Opcode.Kind.CONSTANT

constant - the constant value

Returns:

a load constant instruction

Throws:

IllegalArgumentException - if the opcode is not Opcode.LDC, Opcode.LDC_W, or Opcode.LDC2_W