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java.lang.foreign

public sealed Interface ValueLayout

A layout that models values of basic data types. Examples of values modeled by a value layout are integral values (either signed or unsigned), floating-point values and address values.

Each value layout has a size, an alignment (both expressed in bytes), a byte order, and a carrier, that is, the Java type that should be used when accessing a region of memory using the value layout.

This class defines useful value layout constants for Java primitive types and addresses.

API Note

Some characteristics of the Java layout constants are platform-dependent. For instance, the byte order of these constants is set to the native byte order, thus making it easy to work with other APIs, such as arrays and java.nio.ByteBuffer.

Implementation Specification

implementing classes and subclasses are immutable, thread-safe and value-based.

Since: 22

Nested and Inner Type Summary

Modifier and Type	Class and Description
public static interface	ValueLayout.OfBoolean A value layout whose carrier is `boolean.class`.
public static interface	ValueLayout.OfByte A value layout whose carrier is `byte.class`.
public static interface	ValueLayout.OfChar A value layout whose carrier is `char.class`.
public static interface	ValueLayout.OfDouble A value layout whose carrier is `double.class`.
public static interface	ValueLayout.OfFloat A value layout whose carrier is `float.class`.
public static interface	ValueLayout.OfInt A value layout whose carrier is `int.class`.
public static interface	ValueLayout.OfLong A value layout whose carrier is `long.class`.
public static interface	ValueLayout.OfShort A value layout whose carrier is `short.class`.

Field Summary

Modifier and Type	Field and Description
public static final AddressLayout	ADDRESS An address layout constant whose size is the same as that of a machine address (`size_t`), byte alignment set to `sizeof(size_t)`, byte order set to `ByteOrder#nativeOrder()`.
public static final AddressLayout	ADDRESS_UNALIGNED An unaligned address layout constant whose size is the same as that of a machine address (`size_t`), and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfBoolean	JAVA_BOOLEAN A value layout constant whose size is the same as that of a Java `boolean`, byte alignment set to 1, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfByte	JAVA_BYTE A value layout constant whose size is the same as that of a Java `byte`, byte alignment set to 1, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfChar	JAVA_CHAR A value layout constant whose size is the same as that of a Java `char`, byte alignment set to 2, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfChar	JAVA_CHAR_UNALIGNED An unaligned value layout constant whose size is the same as that of a Java `char` and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfDouble	JAVA_DOUBLE A value layout constant whose size is the same as that of a Java `double`, byte alignment set to 8, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfDouble	JAVA_DOUBLE_UNALIGNED An unaligned value layout constant whose size is the same as that of a Java `double` and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfFloat	JAVA_FLOAT A value layout constant whose size is the same as that of a Java `float`, byte alignment set to 4, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfFloat	JAVA_FLOAT_UNALIGNED An unaligned value layout constant whose size is the same as that of a Java `float` and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfInt	JAVA_INT A value layout constant whose size is the same as that of a Java `int`, byte alignment set to 4, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfInt	JAVA_INT_UNALIGNED An unaligned value layout constant whose size is the same as that of a Java `int` and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfLong	JAVA_LONG A value layout constant whose size is the same as that of a Java `long`, byte alignment set to 8, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfLong	JAVA_LONG_UNALIGNED An unaligned value layout constant whose size is the same as that of a Java `long` and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfShort	JAVA_SHORT A value layout constant whose size is the same as that of a Java `short`, byte alignment set to 2, and byte order set to `ByteOrder#nativeOrder()`.
public static final ValueLayout.OfShort	JAVA_SHORT_UNALIGNED An unaligned value layout constant whose size is the same as that of a Java `short` and byte order set to `ByteOrder#nativeOrder()`.

Method Summary

Modifier and Type	Method and Description
public Class<?>	Returns: the carrier associated with this value layout carrier() Returns the carrier associated with this value layout.
public ByteOrder	Returns: the value's byte order order() Returns the value's byte order.
public VarHandle	Returns: a var handle which can be used to access values described by this value layout, in a given memory segment varHandle() Returns a var handle which can be used to access values described by this value layout, in a given memory segment.
public ValueLayout	withByteAlignment(long byteAlignment) Redeclares java.lang.foreign.MemoryLayout.withByteAlignment. Returns a memory layout with the same characteristics as this layout, but with the given alignment constraint (in bytes).
public ValueLayout	withName(String name) Redeclares java.lang.foreign.MemoryLayout.withName. Returns a memory layout with the same characteristics as this layout, but with the given name.
public ValueLayout	Returns: a value layout with the same characteristics as this layout, but with the given byte order withOrder(ByteOrder the desired byte order order) Returns a value layout with the same characteristics as this layout, but with the given byte order.
public ValueLayout	withoutName() Redeclares java.lang.foreign.MemoryLayout.withoutName. Returns a memory layout with the same characteristics as this layout, but with no name.

Inherited from java.lang.foreign.MemoryLayout:: arrayElementVarHandle byteAlignment byteOffset byteOffsetHandle byteSize equals hashCode name paddingLayout scale scaleHandle select sequenceLayout sliceHandle structLayout toString unionLayout varHandle