Module jdk.incubator.foreign
Package jdk.incubator.foreign

Class FunctionDescriptor

java.lang.Object
jdk.incubator.foreign.FunctionDescriptor
All Implemented Interfaces:
Constable
public sealed class FunctionDescriptor extends Object implements Constable
A function descriptor is made up of zero or more argument layouts and zero or one return layout. A function descriptor is used to model the signature of foreign functions.

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.

  • Method Details

    • returnLayout

      public Optional<MemoryLayout> returnLayout()
      Returns the return layout (if any) associated with this function descriptor.
      Returns:
      the return layout (if any) associated with this function descriptor

    • argumentLayouts

      public List<MemoryLayout> argumentLayouts()
      Returns the argument layouts associated with this function descriptor..
      Returns:
      the argument layouts associated with this function descriptor

    • of

      public static FunctionDescriptor of(MemoryLayout resLayout, MemoryLayout... argLayouts)
      Create a function descriptor with given return and argument layouts.
      Parameters:
      resLayout - the return layout.
      argLayouts - the argument layouts.
      Returns:
      the new function descriptor.

    • ofVoid

      public static FunctionDescriptor ofVoid(MemoryLayout... argLayouts)
      Create a function descriptor with given argument layouts and no return layout.
      Parameters:
      argLayouts - the argument layouts.
      Returns:
      the new function descriptor.

    • asVariadic

      public FunctionDescriptor asVariadic(MemoryLayout... variadicLayouts)
      Obtain a specialized variadic function descriptor, by appending given variadic layouts to this function descriptor argument layouts. The resulting function descriptor can report the position of the first variadic argument, and cannot be altered in any way: for instance, calling changeReturnLayout(MemoryLayout) on the resulting descriptor will throw an UnsupportedOperationException.
      Parameters:
      variadicLayouts - the variadic argument layouts to be appended to this descriptor argument layouts.
      Returns:
      a new variadic function descriptor, or this descriptor if variadicLayouts.length == 0.

    • firstVariadicArgumentIndex

      public int firstVariadicArgumentIndex()
      The index of the first variadic argument layout (where defined).
      Returns:
      The index of the first variadic argument layout, or -1 if this is not a variadic layout.

    • appendArgumentLayouts

      public FunctionDescriptor appendArgumentLayouts(MemoryLayout... addedLayouts)
      Create a new function descriptor with the given argument layouts appended to the argument layout array of this function descriptor.
      Parameters:
      addedLayouts - the argument layouts to append.
      Returns:
      the new function descriptor.

    • insertArgumentLayouts

      public FunctionDescriptor insertArgumentLayouts(int index, MemoryLayout... addedLayouts)
      Create a new function descriptor with the given argument layouts inserted at the given index, into the argument layout array of this function descriptor.
      Parameters:
      index - the index at which to insert the arguments
      addedLayouts - the argument layouts to insert at given index.
      Returns:
      the new function descriptor.
      Throws:
      IllegalArgumentException - if index < 0 || index > argumentLayouts().size().

    • changeReturnLayout

      public FunctionDescriptor changeReturnLayout(MemoryLayout newReturn)
      Create a new function descriptor with the given memory layout as the new return layout.
      Parameters:
      newReturn - the new return layout.
      Returns:
      the new function descriptor.

    • dropReturnLayout

      public FunctionDescriptor dropReturnLayout()
      Create a new function descriptor with the return layout dropped. This is useful to model functions which return no values.
      Returns:
      the new function descriptor.

    • toString

      public String toString()
      Returns the string representation of this function descriptor.
      Overrides:
      toString in class Object
      Returns:
      the string representation of this function descriptor

    • equals

      public boolean equals(Object other)
      Compares the specified object with this function descriptor for equality. Returns true if and only if the specified object is also a function descriptor, and all the following conditions are met:
      Overrides:
      equals in class Object
      Parameters:
      other - the object to be compared for equality with this function descriptor.
      Returns:
      true if the specified object is equal to this function descriptor.
      See Also:

    • hashCode

      public int hashCode()
      Returns the hash code value for this function descriptor.
      Overrides:
      hashCode in class Object
      Returns:
      the hash code value for this function descriptor
      See Also:

    • describeConstable

      public Optional<DynamicConstantDesc<FunctionDescriptor>> describeConstable()
      Returns an Optional containing the nominal descriptor for this function descriptor, if one can be constructed, or an empty Optional if one cannot be constructed.
      Specified by:
      describeConstable in interface Constable
      Returns:
      An Optional containing the resulting nominal descriptor, or an empty Optional if one cannot be constructed.