Enum Class TypeKind
- All Implemented Interfaces:
Serializable,Comparable<TypeKind>,Constable
Describes the data types Java Virtual Machine operates on. This omits
returnAddress (JVMS 2.3.3) and includes void (JVMS
4.3.3), which appears as a method return type.
The returnAddress type is only used by discontinued
jump subroutine and
return from subroutine
instructions. Jump subroutine instructions push returnAddress to the
operand stack; astore instructions store
returnAddress from the operand stack to local variables; return from
subroutine instructions load returnAddress from local variables.
Computational Type
In theclass file format, local variables (JVMS 2.6.1),
and the operand stack (JVMS 2.6.2) of the Java Virtual Machine,
boolean, byte, char,
short types do not exist and are represented by the int computational type.
int, float, reference,
returnAddress, long, and doule
are the computational types of the Java Virtual Machine.- See Java Virtual Machine Specification:
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2.2 Data Types
2.11.1 Types and the Java Virtual Machine - Since:
- 24
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Nested Class Summary
Nested classes/interfaces declared in class java.lang.Enum
Enum.EnumDesc<E extends Enum<E>> -
Enum Constant Summary
Enum ConstantsEnum ConstantDescriptionThe primitive typeboolean.The primitive typebyte.The primitive typechar.The primitive typedouble.The primitive typefloat.The primitive typeint.The primitive typelong.A reference type.The primitive typeshort.Thevoidtype, for absence of a value. -
Method Summary
Modifier and TypeMethodDescriptionstatic TypeKindfrom(TypeDescriptor.OfField<?> descriptor) Returns the type associated with the specified field descriptor.static TypeKindReturns the type associated with the specified field descriptor.static TypeKindfromNewarrayCode(int newarrayCode) Returns the component type described by the array code used as an operand tonewarray.intReturns the code used by thenewarrayinstruction to create an array of this component type, or-1if this type is not supported bynewarray.intslotSize()Returns the number of local variable index or operand stack depth consumed by this type.Returns the most specific upper bound field descriptor that can store any value of this type.static TypeKindReturns the enum constant of this class with the specified name.static TypeKind[]values()Returns an array containing the constants of this enum class, in the order they are declared.
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Enum Constant Details
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BOOLEAN
The primitive typeboolean. Its computational type isint.0representsfalse, and1representstrue. It is zero-extended to anintwhen loaded onto the operand stack and narrowed by taking the bitwise AND with1when stored.- See Java Virtual Machine Specification:
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2.3.4 The
booleanType
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BYTE
The primitive typebyte. Its computational type isint. It is sign-extended to anintwhen loaded onto the operand stack and truncated when stored. -
CHAR
The primitive typechar. Its computational type isint. It is zero-extended to anintwhen loaded onto the operand stack and truncated when stored. -
SHORT
The primitive typeshort. Its computational type isint. It is sign-extended to anintwhen loaded onto the operand stack and truncated when stored. -
INT
The primitive typeint. -
LONG
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FLOAT
The primitive typefloat. All NaN values offloatmay or may not be collapsed into a single "canonical" NaN value in loading and storing. -
DOUBLE
The primitive typedouble. It is of category 2. All NaN values ofdoublemay or may not be collapsed into a single "canonical" NaN value in loading and storing. -
REFERENCE
A reference type.- See Java Virtual Machine Specification:
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2.4 Reference Types and Values
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VOID
Thevoidtype, for absence of a value. While this is not a data type, this can be a method return type indicating no change in operand stack depth.- See Java Virtual Machine Specification:
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4.3.3 Method Descriptors
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Method Details
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values
Returns an array containing the constants of this enum class, in the order they are declared.- Returns:
- an array containing the constants of this enum class, in the order they are declared
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valueOf
Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)- Parameters:
name- the name of the enum constant to be returned.- Returns:
- the enum constant with the specified name
- Throws:
IllegalArgumentException- if this enum class has no constant with the specified nameNullPointerException- if the argument is null
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upperBound
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newarrayCode
public int newarrayCode()Returns the code used by thenewarrayinstruction to create an array of this component type, or-1if this type is not supported bynewarray.- Returns:
- the code used by the
newarrayinstruction to create an array of this component type, or-1if this type is not supported bynewarray - See Java Virtual Machine Specification:
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6.5.newarray newarray
- See Also:
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slotSize
public int slotSize()Returns the number of local variable index or operand stack depth consumed by this type. This is also the category of this type for instructions operating on the operand stack without regard to type (JVMS 2.11.1), such aspopversuspop2.- Returns:
- the number of local variable index or operand stack depth consumed by this type
- See Java Virtual Machine Specification:
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2.6.1 Local Variables
2.6.2 Operand Stacks
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asLoadable
- Returns:
- the computational type for this type, or
voidforvoid - See Also:
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fromNewarrayCode
Returns the component type described by the array code used as an operand tonewarray.- Parameters:
newarrayCode- the operand of thenewarrayinstruction- Returns:
- the component type described by the array code used as an operand to
newarray - Throws:
IllegalArgumentException- if the code is invalid- See Java Virtual Machine Specification:
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6.5.newarray newarray
- See Also:
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fromDescriptor
Returns the type associated with the specified field descriptor.- Parameters:
s- the field descriptor- Returns:
- the type associated with the specified field descriptor
- Throws:
IllegalArgumentException- only if the descriptor is not valid
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from
Returns the type associated with the specified field descriptor.- Parameters:
descriptor- the field descriptor- Returns:
- the type associated with the specified field descriptor
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