- All Implemented Interfaces:
Serializable
,Comparable<AccessFlag>
,Constable
JVM access and module-related flags are related to, but distinct
from Java language modifiers. Some modifiers
and access flags have a one-to-one correspondence, such as
public
. In other cases, some language-level modifiers do
not have an access flag, such as sealed
(JVMS
4.7.31) and some access flags have no corresponding
modifier, such as synthetic.
The values for the constants representing the access and module flags are taken from sections of The Java Virtual Machine Specification including 4.1 (class access and property modifiers), 4.5 (field access and property flags), 4.6 (method access and property flags), 4.7.6 (nested class access and property flags), 4.7.24 (method parameters), and 4.7.25 (module flags and requires, exports, and opens flags).
The mask values for the different access
flags are not distinct. Flags are defined for different
kinds of JVM structures and the same bit position has different
meanings in different contexts. For example, 0x0000_0040
indicates a volatile
field but a bridge method; 0x0000_0080
indicates a transient
field but a variable
arity (varargs) method.
- API Note:
- The JVM class file format has a new version defined for each new
feature release. A new class
file version may define new access flags or retire old ones.
AccessFlag
is intended to model the set of access flags across class file format versions. The range of versions an access flag is recognized is not explicitly indicated in this API. See the current The Java Virtual Machine Specification for details. Unless otherwise indicated, access flags can be assumed to be recognized in the current version. - Implementation Requirements:
- The access flag constants are ordered by non-decreasing mask value; that is the mask value of a constant is greater than or equal to the mask value of an immediate neighbor to its (syntactic) left. If new constants are added, this property will be maintained. That implies new constants will not necessarily be added at the end of the existing list.
- Since:
- 20
- See Also:
-
Nested Class Summary
Modifier and TypeClassDescriptionstatic enum
A location within a class file where flags can be applied.Nested classes/interfaces declared in class java.lang.Enum
Enum.EnumDesc<E extends Enum<E>>
-
Enum Constant Summary
Enum ConstantDescriptionThe access flagACC_ANNOTATION
with a mask value of0x2000
.The access flagACC_BRIDGE
with a mask value of0x0040
The access flagACC_ENUM
with a mask value of0x4000
.The access flagACC_INTERFACE
with a mask value of0x0200
.The access flagACC_MANDATED
with a mask value of0x8000
.The access flagACC_MODULE
with a mask value of0x8000
.The module flagACC_OPEN
with a mask value of0x0020
.The module requires flagACC_STATIC_PHASE
with a mask value of0x0040
.The access flagACC_SUPER
with a mask value of0x0020
.The access flagACC_SYNCHRONIZED
, corresponding to the source modifiersynchronized
, with a mask value of0x0020
.The access flagACC_SYNTHETIC
with a mask value of0x1000
.The module requires flagACC_TRANSITIVE
with a mask value of0x0020
.The access flagACC_VARARGS
with a mask value of0x0080
. -
Method Summary
Modifier and TypeMethodDescriptionReturns kinds of constructs the flag can be applied to in the latest class file format version.Returns kinds of constructs the flag can be applied to in the given class file format version.int
mask()
Returns the corresponding integer mask for the access flag.static Set
<AccessFlag> maskToAccessFlags
(int mask, AccessFlag.Location location) Returns an unmodifiable set of access flags for the given mask value appropriate for the location in question.boolean
Returns whether or not the flag has a directly corresponding modifier in the Java programming language.static AccessFlag
Returns the enum constant of this class with the specified name.static AccessFlag[]
values()
Returns an array containing the constants of this enum class, in the order they are declared.
-
Enum Constant Details
-
PUBLIC
-
PRIVATE
-
PROTECTED
-
STATIC
-
FINAL
-
SUPER
The access flagACC_SUPER
with a mask value of0x0020
.- API Note:
- In Java SE 8 and above, the JVM treats the
ACC_SUPER
flag as set in every class file (JVMS 4.1).
-
OPEN
The module flagACC_OPEN
with a mask value of0x0020
.- See Also:
-
TRANSITIVE
The module requires flagACC_TRANSITIVE
with a mask value of0x0020
.- See Also:
-
SYNCHRONIZED
The access flagACC_SYNCHRONIZED
, corresponding to the source modifiersynchronized
, with a mask value of0x0020
. -
STATIC_PHASE
The module requires flagACC_STATIC_PHASE
with a mask value of0x0040
.- See Also:
-
VOLATILE
-
BRIDGE
The access flagACC_BRIDGE
with a mask value of0x0040
- See Also:
-
TRANSIENT
-
VARARGS
The access flagACC_VARARGS
with a mask value of0x0080
.- See Also:
-
NATIVE
-
INTERFACE
The access flagACC_INTERFACE
with a mask value of0x0200
.- See Also:
-
ABSTRACT
-
STRICT
The access flagACC_STRICT
, corresponding to the source modifierstrictfp
, with a mask value of0x0800
.- API Note:
- The
ACC_STRICT
access flag is defined for class file major versions 46 through 60, inclusive (JVMS 4.6), corresponding to Java SE 1.2 through 16.
-
SYNTHETIC
The access flagACC_SYNTHETIC
with a mask value of0x1000
.- See Also:
-
ANNOTATION
The access flagACC_ANNOTATION
with a mask value of0x2000
.- See Also:
-
ENUM
The access flagACC_ENUM
with a mask value of0x4000
.- See Also:
-
MANDATED
The access flagACC_MANDATED
with a mask value of0x8000
. -
MODULE
The access flagACC_MODULE
with a mask value of0x8000
.
-
-
Method Details
-
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
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
-
mask
public int mask()Returns the corresponding integer mask for the access flag.- Returns:
- the corresponding integer mask for the access flag
-
sourceModifier
public boolean sourceModifier()Returns whether or not the flag has a directly corresponding modifier in the Java programming language.- Returns:
- whether or not the flag has a directly corresponding modifier in the Java programming language
-
locations
Returns kinds of constructs the flag can be applied to in the latest class file format version.- Returns:
- kinds of constructs the flag can be applied to in the latest class file format version
-
locations
Returns kinds of constructs the flag can be applied to in the given class file format version.- Parameters:
cffv
- the class file format version to use- Returns:
- kinds of constructs the flag can be applied to in the given class file format version
- Throws:
NullPointerException
- if the parameter isnull
-
maskToAccessFlags
Returns an unmodifiable set of access flags for the given mask value appropriate for the location in question.- Parameters:
mask
- bit mask of access flagslocation
- context to interpret mask value- Returns:
- an unmodifiable set of access flags for the given mask value appropriate for the location in question
- Throws:
IllegalArgumentException
- if the mask contains bit positions not support for the location in question
-