Module java.base

Package java.lang.foreign

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 layout^PREVIEW; conversely, if all member layouts are laid out at the same starting offset, the resulting group layout is a union layout^PREVIEW.

Implementation Requirements:

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

Sealed Class Hierarchy Graph:

Since:

19

Nested Class Summary

Nested classes/interfaces declared in interface java.lang.foreign.MemoryLayout^PREVIEW

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.MemoryLayout^PREVIEW

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:

• MemoryLayout.name()^PREVIEW

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:

• MemoryLayout.name()^PREVIEW

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.