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Interface MethodTypeDesc

All Superinterfaces:
ConstantDesc, TypeDescriptor, TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc> 
public sealed interface MethodTypeDesc extends ConstantDesc, TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
A nominal descriptor for a MethodType constant.
Since:
12

Nested Class Summary

Nested classes/interfaces declared in interface java.lang.invoke.TypeDescriptor

TypeDescriptor.OfField<F extends TypeDescriptor.OfField<F>>, TypeDescriptor.OfMethod<F extends TypeDescriptor.OfField<F>,M extends TypeDescriptor.OfMethod<F,M>>

Method Summary

Modifier and Type Method Description
MethodTypeDesc changeParameterType(int index, ClassDesc paramType)
Returns a MethodTypeDesc that is identical to this one, except that a single parameter type has been changed to the specified type.
MethodTypeDesc changeReturnType(ClassDesc returnType)
Returns a MethodTypeDesc that is identical to this one, except with the specified return type.
String descriptorString()
Returns the method type descriptor string.
default String displayDescriptor()
Returns a human-readable descriptor for this method type, using the canonical names for parameter and return types.
MethodTypeDesc dropParameterTypes(int start, int end)
Returns a MethodTypeDesc that is identical to this one, except that a range of parameter types have been removed.
boolean equals(Object o)
Compares the specified object with this descriptor for equality.
MethodTypeDesc insertParameterTypes(int pos, ClassDesc... paramTypes)
Returns a MethodTypeDesc that is identical to this one, except that a range of additional parameter types have been inserted.
static MethodTypeDesc of(ClassDesc returnDesc)
Returns a MethodTypeDesc with the given return type and no parameter types.
static MethodTypeDesc of(ClassDesc returnDesc, ClassDesc... paramDescs)
Returns a MethodTypeDesc given the return type and parameter types.
static MethodTypeDesc of(ClassDesc returnDesc, List<ClassDesc> paramDescs)
Returns a MethodTypeDesc given the return type and a list of parameter types.
static MethodTypeDesc ofDescriptor(String descriptor)
Creates a MethodTypeDesc given a method descriptor string.
ClassDesc[] parameterArray()
Returns the parameter types as an array.
int parameterCount()
Returns the number of parameters of the method type described by this MethodTypeDesc.
List<ClassDesc> parameterList()
Returns the parameter types as an immutable List.
ClassDesc parameterType(int index)
Returns the parameter type of the index'th parameter of the method type described by this MethodTypeDesc.
MethodType resolveConstantDesc(MethodHandles.Lookup lookup)
Resolves this descriptor reflectively, emulating the resolution behavior of JVMS 5.4.3 and the access control behavior of JVMS 5.4.4.
ClassDesc returnType()
Gets the return type of the method type described by this MethodTypeDesc.

Method Details

ofDescriptor

static MethodTypeDesc ofDescriptor(String descriptor)
Creates a MethodTypeDesc given a method descriptor string.
Parameters:
descriptor - a method descriptor string
Returns:
a MethodTypeDesc describing the desired method type
Throws:
NullPointerException - if the argument is null
IllegalArgumentException - if the descriptor string is not a valid method descriptor
See Java Virtual Machine Specification:
4.3.3 Method Descriptors

of

static MethodTypeDesc of(ClassDesc returnDesc)
Returns a MethodTypeDesc with the given return type and no parameter types.
Parameters:
returnDesc - a ClassDesc describing the return type
Returns:
a MethodTypeDesc with the given return type and no parameter types
Throws:
NullPointerException - if returnDesc is null
Since:
21

of

static MethodTypeDesc of(ClassDesc returnDesc, List<ClassDesc> paramDescs)
Returns a MethodTypeDesc given the return type and a list of parameter types.
Parameters:
returnDesc - a ClassDesc describing the return type
paramDescs - a List of ClassDescs describing the parameter types
Returns:
a MethodTypeDesc given the return type and a list of parameter types
Throws:
NullPointerException - if any argument or its contents are null
IllegalArgumentException - if any element of paramDescs is a ClassDesc for void
Since:
21

of

static MethodTypeDesc of(ClassDesc returnDesc, ClassDesc... paramDescs)
Returns a MethodTypeDesc given the return type and parameter types.
Parameters:
returnDesc - a ClassDesc describing the return type
paramDescs - ClassDescs describing the argument types
Returns:
a MethodTypeDesc describing the desired method type
Throws:
NullPointerException - if any argument or its contents are null
IllegalArgumentException - if any element of paramDescs is a ClassDesc for void

returnType

ClassDesc returnType()
Gets the return type of the method type described by this MethodTypeDesc.
Specified by:
returnType in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Returns:
a ClassDesc describing the return type of the method type

parameterCount

int parameterCount()
Returns the number of parameters of the method type described by this MethodTypeDesc.
Specified by:
parameterCount in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Returns:
the number of parameters

parameterType

ClassDesc parameterType(int index)
Returns the parameter type of the index'th parameter of the method type described by this MethodTypeDesc.
Specified by:
parameterType in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Parameters:
index - the index of the parameter to retrieve
Returns:
a ClassDesc describing the desired parameter type
Throws:
IndexOutOfBoundsException - if the index is outside the half-open range [0, parameterCount())

parameterList

List<ClassDesc> parameterList()
Returns the parameter types as an immutable List.
Specified by:
parameterList in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Returns:
a List of ClassDesc describing the parameter types

parameterArray

ClassDesc[] parameterArray()
Returns the parameter types as an array.
Specified by:
parameterArray in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Returns:
an array of ClassDesc describing the parameter types

changeReturnType

MethodTypeDesc changeReturnType(ClassDesc returnType)
Returns a MethodTypeDesc that is identical to this one, except with the specified return type.
Specified by:
changeReturnType in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Parameters:
returnType - a ClassDesc describing the new return type
Returns:
a MethodTypeDesc describing the desired method type
Throws:
NullPointerException - if the argument is null

changeParameterType

MethodTypeDesc changeParameterType(int index, ClassDesc paramType)
Returns a MethodTypeDesc that is identical to this one, except that a single parameter type has been changed to the specified type.
Specified by:
changeParameterType in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Parameters:
index - the index of the parameter to change
paramType - a ClassDesc describing the new parameter type
Returns:
a MethodTypeDesc describing the desired method type
Throws:
NullPointerException - if any argument is null
IndexOutOfBoundsException - if the index is outside the half-open range [0, parameterCount)

dropParameterTypes

MethodTypeDesc dropParameterTypes(int start, int end)
Returns a MethodTypeDesc that is identical to this one, except that a range of parameter types have been removed.
Specified by:
dropParameterTypes in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Parameters:
start - the index of the first parameter to remove
end - the index after the last parameter to remove
Returns:
a MethodTypeDesc describing the desired method type
Throws:
IndexOutOfBoundsException - if start is outside the half-open range [0, parameterCount), or end is outside the closed range [0, parameterCount], or if start > end

insertParameterTypes

MethodTypeDesc insertParameterTypes(int pos, ClassDesc... paramTypes)
Returns a MethodTypeDesc that is identical to this one, except that a range of additional parameter types have been inserted.
Specified by:
insertParameterTypes in interface TypeDescriptor.OfMethod<ClassDesc,MethodTypeDesc>
Parameters:
pos - the index at which to insert the first inserted parameter
paramTypes - ClassDescs describing the new parameter types to insert
Returns:
a MethodTypeDesc describing the desired method type
Throws:
NullPointerException - if any argument or its contents are null
IndexOutOfBoundsException - if pos is outside the closed range [0, parameterCount]
IllegalArgumentException - if any element of paramTypes is a ClassDesc for void

descriptorString

String descriptorString()
Returns the method type descriptor string.
Specified by:
descriptorString in interface TypeDescriptor
Returns:
the method type descriptor string
See Java Virtual Machine Specification:
4.3.3 Method Descriptors

displayDescriptor

default String displayDescriptor()
Returns a human-readable descriptor for this method type, using the canonical names for parameter and return types.
Returns:
the human-readable descriptor for this method type

resolveConstantDesc

MethodType resolveConstantDesc(MethodHandles.Lookup lookup) throws ReflectiveOperationException
Resolves this descriptor reflectively, emulating the resolution behavior of JVMS 5.4.3 and the access control behavior of JVMS 5.4.4. The resolution and access control context is provided by the MethodHandles.Lookup parameter. No caching of the resulting value is performed.
Specified by:
resolveConstantDesc in interface ConstantDesc
API Note:
MethodTypeDesc can represent method type descriptors that are not representable by MethodType, such as methods with more than 255 parameter slots, so attempts to resolve these may result in errors.
Parameters:
lookup - The MethodHandles.Lookup to provide name resolution and access control context
Returns:
the resolved constant value
Throws:
ReflectiveOperationException - if a class, method, or field could not be reflectively resolved in the course of resolution

equals

boolean equals(Object o)
Compares the specified object with this descriptor for equality. Returns true if and only if the specified object is also a MethodTypeDesc both have the same arity, their return types are equal, and each pair of corresponding parameter types are equal.
Overrides:
equals in class Object
Parameters:
o - the other object
Returns:
whether this descriptor is equal to the other object
See Also:

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/constant/MethodTypeDesc.html