- Enclosing interface:
MemoryLayoutPREVIEW
public static sealed interface MemoryLayout.PathElement
PathElement is a preview API of the Java platform.
Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.
An element in a layout path. There
are three kinds of path elements:
- group path elements, used to select a member layout within a
GroupLayoutPREVIEW, either by name or by index; - sequence path elements, used to select one or more sequence element layouts within a
SequenceLayoutPREVIEW; and - dereference path elements, used to dereference an address layout as its target layout.
- Implementation Requirements:
- Implementations of this interface are immutable, thread-safe and value-based.
- Since:
- 19
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Method Summary
Static MethodsModifier and TypeMethodDescriptionReturns a path element which dereferences an address layout as its target layoutPREVIEW (where set).groupElement(long index) Returns a path element which selects a member layout with the given index in a group layout.groupElement(String name) Returns a path element which selects a member layout with the given name in a group layout.Returns an open path element which selects an unspecified element layout in a sequence layout.sequenceElement(long index) Returns a path element which selects the element layout at the specified position in a sequence layout.sequenceElement(long start, long step) Returns an open path element which selects the element layout in a range of positions in a sequence layout.
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Method Details
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groupElement
Returns a path element which selects a member layout with the given name in a group layout.- Implementation Requirements:
- in case multiple group elements with a matching name exist, the path element returned by this
method will select the first one; that is, the group element with the lowest offset from current path is selected.
In such cases, using
groupElement(long)might be preferable. - Parameters:
name- the name of the member layout to be selected.- Returns:
- a path element which selects the group member layout with the given name.
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groupElement
Returns a path element which selects a member layout with the given index in a group layout.- Parameters:
index- the index of the member layout element to be selected.- Returns:
- a path element which selects the group member layout with the given index.
- Throws:
IllegalArgumentException- ifindex < 0.
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sequenceElement
Returns a path element which selects the element layout at the specified position in a sequence layout.- Parameters:
index- the index of the sequence element to be selected.- Returns:
- a path element which selects the sequence element layout with the given index.
- Throws:
IllegalArgumentException- ifindex < 0.
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sequenceElement
Returns an open path element which selects the element layout in a range of positions in a sequence layout. The range is expressed as a pair of starting index (inclusive)Sand step factor (which can also be negative)F.The exact sequence element selected by this layout is expressed as an index
I. IfCis the sequence element count, it follows that0 <= I < B, whereBis computed as follows:- if
F > 0, thenB = ceilDiv(C - S, F) - if
F < 0, thenB = ceilDiv(-(S + 1), -F)
- Parameters:
start- the index of the first sequence element to be selected.step- the step factor at which subsequence sequence elements are to be selected.- Returns:
- a path element which selects the sequence element layout with the given index.
- Throws:
IllegalArgumentException- ifstart < 0, orstep == 0.
- if
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sequenceElement
Returns an open path element which selects an unspecified element layout in a sequence layout.The exact sequence element selected by this layout is expressed as an index
I. IfCis the sequence element count, it follows that0 <= I < C.- Returns:
- a path element which selects an unspecified sequence element layout.
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dereferenceElement
Returns a path element which dereferences an address layout as its target layoutPREVIEW (where set).- Returns:
- a path element which dereferences an address layout.
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PathElementwhen preview features are enabled.