Module java.base

Package java.lang.classfile^PREVIEW

Interface ClassBuilder

All Superinterfaces:

ClassFileBuilderPREVIEW<ClassElementPREVIEW,ClassBuilderPREVIEW>, Consumer<ClassElementPREVIEW>

public sealed interface ClassBuilder
extends ClassFileBuilderPREVIEW<ClassElementPREVIEW,ClassBuilderPREVIEW>

ClassBuilder is a preview API of the Java platform.

Programs can only use ClassBuilder when preview features are enabled.

Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.

A builder for classfiles. Builders are not created directly; they are passed to handlers by methods such as ClassFile.build(ClassDesc, Consumer)^PREVIEW or to class transforms. The elements of a classfile can be specified abstractly (by passing a ClassElement^PREVIEW to ClassFileBuilder.with(ClassFileElement)^PREVIEW) or concretely by calling the various withXxx methods.

Since:

22

See Also:

• ClassTransform^PREVIEW

Method Summary

Modifier and Type	Method	Description
Optional<ClassModelPREVIEW>	original()	Returns the ClassModelPREVIEW representing the class being transformed, if this class builder represents the transformation of some ClassModelPREVIEW.
ClassBuilderPREVIEW	transformField(FieldModelPREVIEW field, FieldTransformPREVIEW transform)	Adds a field by transforming a field from another class.
ClassBuilderPREVIEW	transformMethod(MethodModelPREVIEW method, MethodTransformPREVIEW transform)	Adds a method by transforming a method from another class.
default ClassBuilderPREVIEW	withField(Utf8EntryPREVIEW name, Utf8EntryPREVIEW descriptor, int flags)	Adds a field.
ClassBuilderPREVIEW	withField(Utf8EntryPREVIEW name, Utf8EntryPREVIEW descriptor, Consumer<? super FieldBuilderPREVIEW> handler)	Adds a field.
default ClassBuilderPREVIEW	withField(String name, ClassDesc descriptor, int flags)	Adds a field.
default ClassBuilderPREVIEW	withField(String name, ClassDesc descriptor, Consumer<? super FieldBuilderPREVIEW> handler)	Adds a field.
default ClassBuilderPREVIEW	withFlags(int flags)	Sets the classfile access flags.
default ClassBuilderPREVIEW	withFlags(AccessFlag... flags)	Sets the classfile access flags.
default ClassBuilderPREVIEW	withInterfaces(ClassEntryPREVIEW... interfaces)	Sets the interfaces of this class.
default ClassBuilderPREVIEW	withInterfaces(List<ClassEntryPREVIEW> interfaces)	Sets the interfaces of this class.
default ClassBuilderPREVIEW	withInterfaceSymbols(ClassDesc... interfaces)	Sets the interfaces of this class.
default ClassBuilderPREVIEW	withInterfaceSymbols(List<ClassDesc> interfaces)	Sets the interfaces of this class.
ClassBuilderPREVIEW	withMethod(Utf8EntryPREVIEW name, Utf8EntryPREVIEW descriptor, int methodFlags, Consumer<? super MethodBuilderPREVIEW> handler)	Adds a method.
default ClassBuilderPREVIEW	withMethod(String name, MethodTypeDesc descriptor, int methodFlags, Consumer<? super MethodBuilderPREVIEW> handler)	Adds a method.
default ClassBuilderPREVIEW	withMethodBody(Utf8EntryPREVIEW name, Utf8EntryPREVIEW descriptor, int methodFlags, Consumer<? super CodeBuilderPREVIEW> handler)	Adds a method, with only a Code attribute.
default ClassBuilderPREVIEW	withMethodBody(String name, MethodTypeDesc descriptor, int methodFlags, Consumer<? super CodeBuilderPREVIEW> handler)	Adds a method, with only a CodeAttributePREVIEW.
default ClassBuilderPREVIEW	withSuperclass(ClassEntryPREVIEW superclassEntry)	Sets the superclass of this class.
default ClassBuilderPREVIEW	withSuperclass(ClassDesc desc)	Sets the superclass of this class.
default ClassBuilderPREVIEW	withVersion(int major, int minor)	Sets the classfile version.

Methods declared in interface java.lang.classfile.ClassFileBuilder^PREVIEW

accept, canWriteDirect, constantPool, transform, with

Methods declared in interface java.util.function.Consumer

andThen

Method Details

original

Optional<ClassModelPREVIEW> original()

Returns the ClassModel^PREVIEW representing the class being transformed, if this class builder represents the transformation of some ClassModel^PREVIEW.

Returns:

the ClassModel^PREVIEW representing the class being transformed, if this class builder represents the transformation of some ClassModel^PREVIEW

withVersion

default ClassBuilderPREVIEW withVersion(int major,
 int minor)

Sets the classfile version.

Parameters:

major - the major version number

minor - the minor version number

Returns:

this builder

withFlags

default ClassBuilderPREVIEW withFlags(int flags)

Sets the classfile access flags.

Parameters:

flags - the access flags, as a bit mask

Returns:

this builder

withFlags

default ClassBuilderPREVIEW withFlags(AccessFlag... flags)

Sets the classfile access flags.

Parameters:

flags - the access flags

Returns:

this builder

withSuperclass

default ClassBuilderPREVIEW withSuperclass(ClassEntryPREVIEW superclassEntry)

Sets the superclass of this class.

Parameters:

superclassEntry - the superclass

Returns:

this builder

withSuperclass

default ClassBuilderPREVIEW withSuperclass(ClassDesc desc)

Sets the superclass of this class.

Parameters:

desc - the superclass

Returns:

this builder

Throws:

IllegalArgumentException - if desc represents a primitive type

withInterfaces

default ClassBuilderPREVIEW withInterfaces(List<ClassEntryPREVIEW> interfaces)

Sets the interfaces of this class.

Parameters:

interfaces - the interfaces

Returns:

this builder

withInterfaces

default ClassBuilderPREVIEW withInterfaces(ClassEntryPREVIEW... interfaces)

Sets the interfaces of this class.

Parameters:

interfaces - the interfaces

Returns:

this builder

withInterfaceSymbols

default ClassBuilderPREVIEW withInterfaceSymbols(List<ClassDesc> interfaces)

Sets the interfaces of this class.

Parameters:

interfaces - the interfaces

Returns:

this builder

withInterfaceSymbols

default ClassBuilderPREVIEW withInterfaceSymbols(ClassDesc... interfaces)

Sets the interfaces of this class.

Parameters:

interfaces - the interfaces

Returns:

this builder

withField

ClassBuilderPREVIEW withField(Utf8EntryPREVIEW name,
 Utf8EntryPREVIEW descriptor,
 Consumer<? super FieldBuilderPREVIEW> handler)

Adds a field.

Parameters:

name - the name of the field

descriptor - the field descriptor

handler - handler which receives a FieldBuilder^PREVIEW which can further define the contents of the field

Returns:

this builder

withField

default ClassBuilderPREVIEW withField(Utf8EntryPREVIEW name,
 Utf8EntryPREVIEW descriptor,
 int flags)

Adds a field.

Parameters:

name - the name of the field

descriptor - the field descriptor

flags - the access flags for this field

Returns:

this builder

withField

default ClassBuilderPREVIEW withField(String name,
 ClassDesc descriptor,
 Consumer<? super FieldBuilderPREVIEW> handler)

Adds a field.

Parameters:

name - the name of the field

descriptor - the field descriptor

handler - handler which receives a FieldBuilder^PREVIEW which can further define the contents of the field

Returns:

this builder

withField

default ClassBuilderPREVIEW withField(String name,
 ClassDesc descriptor,
 int flags)

Adds a field.

Parameters:

name - the name of the field

descriptor - the field descriptor

flags - the access flags for this field

Returns:

this builder

transformField

ClassBuilderPREVIEW transformField(FieldModelPREVIEW field,
 FieldTransformPREVIEW transform)

Adds a field by transforming a field from another class.

Implementation Note:

This method behaves as if:

    withField(field.fieldName(), field.fieldType(),
               b -> b.transformField(field, transform));

Parameters:

field - the field to be transformed

transform - the transform to apply to the field

Returns:

this builder

withMethod

ClassBuilderPREVIEW withMethod(Utf8EntryPREVIEW name,
 Utf8EntryPREVIEW descriptor,
 int methodFlags,
 Consumer<? super MethodBuilderPREVIEW> handler)

Adds a method.

Parameters:

name - the name of the method

descriptor - the method descriptor

methodFlags - the access flags

handler - handler which receives a MethodBuilder^PREVIEW which can further define the contents of the method

Returns:

this builder

withMethodBody

default ClassBuilderPREVIEW withMethodBody(Utf8EntryPREVIEW name,
 Utf8EntryPREVIEW descriptor,
 int methodFlags,
 Consumer<? super CodeBuilderPREVIEW> handler)

Adds a method, with only a Code attribute.

Parameters:

name - the name of the method

descriptor - the method descriptor

methodFlags - the access flags

handler - handler which receives a CodeBuilder^PREVIEW which can define the contents of the method body

Returns:

this builder

withMethod

default ClassBuilderPREVIEW withMethod(String name,
 MethodTypeDesc descriptor,
 int methodFlags,
 Consumer<? super MethodBuilderPREVIEW> handler)

Adds a method.

Parameters:

name - the name of the method

descriptor - the method descriptor

methodFlags - the access flags

handler - handler which receives a MethodBuilder^PREVIEW which can further define the contents of the method

Returns:

this builder

withMethodBody

default ClassBuilderPREVIEW withMethodBody(String name,
 MethodTypeDesc descriptor,
 int methodFlags,
 Consumer<? super CodeBuilderPREVIEW> handler)

Adds a method, with only a CodeAttribute^PREVIEW.

Parameters:

name - the name of the method

descriptor - the method descriptor

methodFlags - the access flags

handler - handler which receives a CodeBuilder^PREVIEW which can define the contents of the method body

Returns:

this builder

transformMethod

ClassBuilderPREVIEW transformMethod(MethodModelPREVIEW method,
 MethodTransformPREVIEW transform)

Adds a method by transforming a method from another class.

Implementation Note:

This method behaves as if:

    withMethod(method.methodName(), method.methodType(),
               b -> b.transformMethod(method, transform));

Parameters:

method - the method to be transformed

transform - the transform to apply to the method

Returns:

this builder