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/OpenJDK 21

Interface GroupLayout

All Superinterfaces:
MemoryLayoutPREVIEW
All Known Subinterfaces:
StructLayoutPREVIEW, UnionLayoutPREVIEW 
public sealed interface GroupLayout extends MemoryLayoutPREVIEW permits StructLayoutPREVIEW, UnionLayoutPREVIEW
GroupLayout is a preview API of the Java platform.
Programs can only use GroupLayout when preview features are enabled.
Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.
A compound layout that is an aggregation of multiple, heterogeneous 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 a struct layoutPREVIEW; conversely, if all member layouts are laid out at the same starting offset, the resulting group layout is a union layoutPREVIEW.
Implementation Requirements:
This class is immutable, thread-safe and value-based.
Sealed Class Hierarchy Graph:
Sealed class hierarchy graph for GroupLayoutSealed class hierarchy graph for GroupLayout
Since:
19

Nested Class Summary

Nested classes/interfaces declared in interface java.lang.foreign.MemoryLayoutPREVIEW

MemoryLayout.PathElementPREVIEW

Method Summary

Modifier and Type Method Description
List<MemoryLayoutPREVIEW> memberLayouts()
Returns the member layouts of this group layout.
GroupLayoutPREVIEW withByteAlignment(long byteAlignment)
Returns a memory layout with the same characteristics as this layout, but with the given alignment constraint (in bytes).
GroupLayoutPREVIEW withName(String name)
Returns a memory layout with the same characteristics as this layout, but with the given name.
GroupLayoutPREVIEW withoutName()
Returns a memory layout with the same characteristics as this layout, but with no name.

Methods declared in interface java.lang.foreign.MemoryLayoutPREVIEW

byteAlignment, byteOffset, byteOffsetHandle, byteSize, equals, hashCode, name, select, sliceHandle, toString, varHandle

Method Details

memberLayouts

List<MemoryLayoutPREVIEW> memberLayouts()
Returns the member layouts of this group layout.
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 of this group layout

withName

GroupLayoutPREVIEW withName(String name)
Returns a memory layout with the same characteristics as this layout, but with the given name.
Specified by:
withName in interface MemoryLayoutPREVIEW
Parameters:
name - the layout name.
Returns:
a memory layout with the same characteristics as this layout, but with the given name
See Also:

withoutName

GroupLayoutPREVIEW withoutName()
Returns a memory layout with the same characteristics as this layout, but with no name.
Specified by:
withoutName in interface MemoryLayoutPREVIEW
Returns:
a memory layout with the same characteristics as this layout, but with no name
See Also:

withByteAlignment

GroupLayoutPREVIEW withByteAlignment(long byteAlignment)
Returns a memory layout with the same characteristics as this layout, but with the given alignment constraint (in bytes).
Specified by:
withByteAlignment in interface MemoryLayoutPREVIEW
Parameters:
byteAlignment - the layout alignment constraint, expressed in bytes.
Returns:
a memory layout with the same characteristics as this layout, but with the given alignment constraint (in bytes)
Throws:
IllegalArgumentException - if byteAlignment is not a power of two.
IllegalArgumentException - if byteAlignment is less than M, where M is the maximum alignment constraint in any of the member layouts associated with this group layout.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/foreign/GroupLayout.html