- Enclosing interface:
- MemoryLayout
public static sealed interface MemoryLayout.PathElement
Instances of this class are used to form layout paths. There
are two kinds of path elements: group path elements and sequence path elements. Group
path elements are used to select a given named member layout within a
GroupLayout. Sequence
path elements are used to select a sequence element layout within a SequenceLayout; selection
of sequence element layout can be explicit (see sequenceElement(long)) or
implicit (see sequenceElement()). When a path uses one or more implicit
sequence path elements, it acquires additional free dimensions.
Non-platform classes should not implement MemoryLayout.PathElement directly.
Unless otherwise specified, passing a null argument, or an array argument containing one or more null
elements to a method in this class causes a NullPointerException to be thrown.
- Implementation Requirements:
- Implementations of this interface are immutable and thread-safe.
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Method Summary
Static MethodsModifier and TypeMethodDescriptionstatic MemoryLayout.PathElementgroupElement(String name) Returns a path element which selects a member layout with given name from a given group layout.static MemoryLayout.PathElementReturns a path element which selects an unspecified element layout from a given sequence layout.static MemoryLayout.PathElementsequenceElement(long index) Returns a path element which selects the element layout at the specified position in a given the sequence layout.static MemoryLayout.PathElementsequenceElement(long start, long step) Returns a path element which selects the element layout in a range of positions in a given the sequence layout, where the range is expressed as a pair of starting index (inclusive)Sand step factor (which can also be negative)F.
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Method Details
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groupElement
Returns a path element which selects a member layout with given name from a given group layout. The path element returned by this method does not alter the number of free dimensions of any path that is combined with such element.- 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 lowest offset from current path is selected.
- Parameters:
name- the name of the group element to be selected.- Returns:
- a path element which selects the group element with given name.
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sequenceElement
Returns a path element which selects the element layout at the specified position in a given the sequence layout. The path element returned by this method does not alter the number of free dimensions of any path that is combined with such element.- Parameters:
index- the index of the sequence element to be selected.- Returns:
- a path element which selects the sequence element layout with given index.
- Throws:
IllegalArgumentException- ifindex < 0.
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sequenceElement
Returns a path element which selects the element layout in a range of positions in a given the sequence layout, where the range is expressed as a pair of starting index (inclusive)Sand step factor (which can also be negative)F. If a path with free dimensionsnis combined with the path element returned by this method, the number of free dimensions of the resulting path will be1 + n. If the free dimension associated with this path is bound by an indexI, the resulting accessed offset can be obtained with the following formula:
whereE * (S + I * F)Eis the size (in bytes) of the sequence element layout.- 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 given index.
- Throws:
IllegalArgumentException- ifstart < 0, orstep == 0.
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sequenceElement
Returns a path element which selects an unspecified element layout from a given sequence layout. If a path with free dimensionsnis combined with the path element returned by this method, the number of free dimensions of the resulting path will be1 + n.- Returns:
- a path element which selects an unspecified sequence element layout.
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