java.lang.Object
java.lang.foreign.GroupLayout
- All Implemented Interfaces:
MemoryLayoutPREVIEW
GroupLayout
is a preview API of the Java platform.
Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.
A compound layout that aggregates multiple member layouts. There are two ways in which member layouts
can be combined: if member layouts are laid out one after the other, the resulting group layout is said to be a struct
(see
MemoryLayout.structLayout(MemoryLayout...)
PREVIEW); conversely, if all member layouts are laid out at the same starting offset,
the resulting group layout is said to be a union (see MemoryLayout.unionLayout(MemoryLayout...)
PREVIEW).- Implementation Requirements:
- This class is immutable, thread-safe and value-based.
- Since:
- 19
-
Nested Class Summary
Nested classes/interfaces declared in interface java.lang.foreign.MemoryLayoutPREVIEW
MemoryLayout.PathElementPREVIEW
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Method Summary
Modifier and TypeMethodDescriptionfinal long
Returns the alignment constraint associated with this layout, expressed in bits.long
bitSize()
Returns the layout size, in bits.long
byteSize()
Returns the layout size, in bytes.boolean
Compares the specified object with this layout for equality.int
hashCode()
Returns the hash code value for this layout.boolean
Returns true, if this layout is a padding layout.boolean
isStruct()
Returnstrue
, if this group layout is a struct layout.boolean
isUnion()
Returnstrue
, if this group layout is a union layout.Returns the member layouts associated with this group.name()
Returns the name (if any) associated with this layout.toString()
Returns the string representation of this layout.withBitAlignment
(long alignmentBits) Returns a memory layout with the same size and name as this layout, but with the specified alignment constraints (in bits).Returns a memory layout with the same size and alignment constraints as this layout, but with the specified name.Methods declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Methods declared in interface java.lang.foreign.MemoryLayoutPREVIEW
bitAlignment, bitOffset, bitOffsetHandle, bitSize, byteAlignment, byteOffset, byteOffsetHandle, byteSize, isPadding, name, select, sliceHandle, varHandle
-
Method Details
-
memberLayouts
Returns the member layouts associated with this group.- API Note:
- the order in which member layouts are returned is the same order in which member layouts have
been passed to one of the group layout factory methods (see
MemoryLayout.structLayout(MemoryLayout...)
PREVIEW,MemoryLayout.unionLayout(MemoryLayout...)
PREVIEW). - Returns:
- the member layouts associated with this group.
-
toString
Returns the string representation of this layout.- Specified by:
toString
in interfaceMemoryLayoutPREVIEW
- Returns:
- the string representation of this layout
-
isStruct
public boolean isStruct()Returnstrue
, if this group layout is a struct layout.- Returns:
true
, if this group layout is a struct layout
-
isUnion
public boolean isUnion()Returnstrue
, if this group layout is a union layout.- Returns:
true
, if this group layout is a union layout
-
equals
Compares the specified object with this layout for equality. Returnstrue
if and only if the specified object is also a layout, and it is equal to this layout. Two layouts are considered equal if they are of the same kind, have the same size, name and alignment constraints. Furthermore, depending on the layout kind, additional conditions must be satisfied:- two value layouts are considered equal if they have the same orderPREVIEW, and carrierPREVIEW
- two sequence layouts are considered equal if they have the same element count (see
SequenceLayout.elementCount()
PREVIEW), and if their element layouts (seeSequenceLayout.elementLayout()
PREVIEW) are also equal - two group layouts are considered equal if they are of the same kind (see
isStruct()
,isUnion()
) and if their member layouts (seememberLayouts()
) are also equal
- Specified by:
equals
in interfaceMemoryLayoutPREVIEW
- Parameters:
other
- the object to be compared for equality with this layout.- Returns:
true
if the specified object is equal to this layout.- See Also:
-
hashCode
public int hashCode()Returns the hash code value for this layout.- Specified by:
hashCode
in interfaceMemoryLayoutPREVIEW
- Returns:
- the hash code value for this layout
- See Also:
-
withName
Returns a memory layout with the same size and alignment constraints as this layout, but with the specified name.- Specified by:
withName
in interfaceMemoryLayoutPREVIEW
- Parameters:
name
- the layout name.- Returns:
- a memory layout with the given name.
- See Also:
-
withBitAlignment
Returns a memory layout with the same size and name as this layout, but with the specified alignment constraints (in bits).- Specified by:
withBitAlignment
in interfaceMemoryLayoutPREVIEW
- Parameters:
alignmentBits
- the layout alignment constraint, expressed in bits.- Returns:
- a memory layout with the given alignment constraints.
-
name
Description copied from interface:MemoryLayout
Returns the name (if any) associated with this layout.- Specified by:
name
in interfaceMemoryLayoutPREVIEW
- Returns:
- the name (if any) associated with this layout
- See Also:
-
bitAlignment
public final long bitAlignment()Description copied from interface:MemoryLayout
Returns the alignment constraint associated with this layout, expressed in bits. Layout alignment defines a power of twoA
which is the bit-wise alignment of the layout. IfA <= 8
thenA/8
is the number of bytes that must be aligned for any pointer that correctly points to this layout. Thus:A=8
means unaligned (in the usual sense), which is common in packets.A=64
means word aligned (on LP64),A=32
int aligned,A=16
short aligned, etc.A=512
is the most strict alignment required by the x86/SV ABI (for AVX-512 data).
MemoryLayout.withBitAlignment(long)
PREVIEW), then this method returns the natural alignment constraint (in bits) associated with this layout.- Specified by:
bitAlignment
in interfaceMemoryLayoutPREVIEW
- Returns:
- the layout alignment constraint, in bits.
-
byteSize
public long byteSize()Description copied from interface:MemoryLayout
Returns the layout size, in bytes.- Specified by:
byteSize
in interfaceMemoryLayoutPREVIEW
- Returns:
- the layout size, in bytes
-
bitSize
public long bitSize()Description copied from interface:MemoryLayout
Returns the layout size, in bits.- Specified by:
bitSize
in interfaceMemoryLayoutPREVIEW
- Returns:
- the layout size, in bits
-
isPadding
public boolean isPadding()Description copied from interface:MemoryLayout
Returns true, if this layout is a padding layout.- Specified by:
isPadding
in interfaceMemoryLayoutPREVIEW
- Returns:
- true, if this layout is a padding layout
-
GroupLayout
when preview features are enabled.