W3cubDocs

/OpenJDK 25

Interface GroupLayout

All Superinterfaces:
MemoryLayout
All Known Subinterfaces:
StructLayout, UnionLayout
public sealed interface GroupLayout extends MemoryLayout permits StructLayout, UnionLayout
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 layout; conversely, if all member layouts are laid out at the same starting offset, the resulting group layout is a union layout.
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:
22

Nested Class Summary

Nested classes/interfaces declared in interface MemoryLayout

MemoryLayout.PathElement

Method Summary

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

Methods declared in interface MemoryLayout

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

Method Details

memberLayouts

List<MemoryLayout> 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...) and MemoryLayout.unionLayout(MemoryLayout...)).
Returns:
the member layouts of this group layout

withName

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

withoutName

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

withByteAlignment

GroupLayout 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 MemoryLayout
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

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
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).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/lang/foreign/GroupLayout.html