Enum Class TypeKind

java.lang.Object
java.lang.Enum<TypeKind>
java.lang.classfile.TypeKind
All Implemented Interfaces:
Serializable, Comparable<TypeKind>, Constable
public enum TypeKind extends Enum<TypeKind>
Describes the data types Java Virtual Machine operates on. This omits returnAddress (JVMS 2.3.3), which is only used by discontinued jsr and ret instructions, and includes void (JVMS 4.3.3), which appears as a method return type.

Computational Type

In the class 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:
2.2 Data Types
2.11.1 Types and the Java Virtual Machine
Since:
24

  • Enum Constant Details

    • BOOLEAN

      public static final TypeKind BOOLEAN
      The primitive type boolean. Its computational type is int. 0 represents false, and 1 represents true. It is zero-extended to an int when loaded onto the operand stack and narrowed by taking the bitwise AND with 1 when stored.
      See Java Virtual Machine Specification:
      2.3.4 The boolean Type

    • BYTE

      public static final TypeKind BYTE
      The primitive type byte. Its computational type is int. It is sign-extended to an int when loaded onto the operand stack and truncated when stored.

    • CHAR

      public static final TypeKind CHAR
      The primitive type char. Its computational type is int. It is zero-extended to an int when loaded onto the operand stack and truncated when stored.

    • SHORT

      public static final TypeKind SHORT
      The primitive type short. Its computational type is int. It is sign-extended to an int when loaded onto the operand stack and truncated when stored.

    • INT

      public static final TypeKind INT
      The primitive type int.

    • LONG

      public static final TypeKind LONG
      The primitive type long. It is of category 2.

    • FLOAT

      public static final TypeKind FLOAT
      The primitive type float.

    • DOUBLE

      public static final TypeKind DOUBLE
      The primitive type double. It is of category 2.

    • REFERENCE

      public static final TypeKind REFERENCE
      A reference type.
      See Java Virtual Machine Specification:
      2.4 Reference Types and Values

    • VOID

      public static final TypeKind VOID
      The void type, 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:
      4.3.3 Method Descriptors

  • Method Details

    • values

      public static TypeKind[] 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

    • valueOf

      public static TypeKind valueOf(String name)
      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 name
      NullPointerException - if the argument is null

    • upperBound

      public ClassDesc upperBound()
      Returns the most specific upper bound field descriptor that can store any value of this type. This is the primitive class descriptor for primitive types and void and Object descriptor for reference.
      Returns:
      the most specific upper bound field descriptor that can store any value of this type

    • newarrayCode

      public int newarrayCode()
      Returns the code used by the newarray instruction to create an array of this component type, or -1 if this type is not supported by newarray.
      Returns:
      the code used by the newarray instruction to create an array of this component type, or -1 if this type is not supported by newarray
      See Java Virtual Machine Specification:
      6.5.newarray newarray

    • 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 as pop versus pop2.
      Returns:
      the number of local variable index or operand stack depth consumed by this type
      See Java Virtual Machine Specification:
      2.6.1 Local Variables
      2.6.2 Operand Stacks

    • asLoadable

      public TypeKind asLoadable()
      Returns the computational type for this type, or void for void.
      Returns:
      the computational type for this type, or void for void

    • fromNewarrayCode

      public static TypeKind fromNewarrayCode(int newarrayCode)
      Returns the component type described by the array code used as an operand to newarray.
      Parameters:
      newarrayCode - the operand of the newarray instruction
      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:
      6.5.newarray newarray

    • fromDescriptor

      public static TypeKind fromDescriptor(CharSequence s)
      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

    • from

      public static TypeKind from(TypeDescriptor.OfField<?> descriptor)
      Returns the type associated with the specified field descriptor.
      Parameters:
      descriptor - the field descriptor
      Returns:
      the type associated with the specified field descriptor