Module java.base

Package java.lang.foreign

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.

Since:

22

Implementation Requirements:

This class is immutable, thread-safe and value-based.

Sealed Graph:

Nested Class Summary

Nested classes/interfaces inherited from interface java.lang.foreign.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 inherited from interface java.lang.foreign.MemoryLayout

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.

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...), MemoryLayout.unionLayout(MemoryLayout...)).

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:

• MemoryLayout.name()

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:

• MemoryLayout.name()

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.