Module java.base

Package java.lang.classfile^PREVIEW

Interface ClassTransform

All Superinterfaces:

ClassFileTransformPREVIEW<ClassTransformPREVIEW,ClassElementPREVIEW,ClassBuilderPREVIEW>

All Known Subinterfaces:

ClassRemapperPREVIEW

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public non-sealed interface ClassTransform
extends ClassFileTransformPREVIEW<ClassTransformPREVIEW,ClassElementPREVIEW,ClassBuilderPREVIEW>

ClassTransform is a preview API of the Java platform.

Programs can only use ClassTransform when preview features are enabled.

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

A transformation on streams of ClassElement^PREVIEW.

Since:

22

See Also:

• ClassFileTransform^PREVIEW

Nested Class Summary

Nested classes/interfaces declared in interface java.lang.classfile.ClassFileTransform^PREVIEW

ClassFileTransform.ResolvedTransformPREVIEW<E extends ClassFileElementPREVIEW>

Field Summary

Fields

Modifier and Type	Field	Description
static final ClassTransformPREVIEW	ACCEPT_ALL	A class transform that sends all elements to the builder.

Method Summary

Modifier and Type	Method	Description
default ClassTransformPREVIEW	andThen(ClassTransformPREVIEW t)	Chain this transform with another; elements presented to the builder of this transform will become the input to the next transform.
static ClassTransformPREVIEW	dropping(Predicate<ClassElementPREVIEW> filter)	Create a class transform that passes each element through to the builder, except for those that the supplied Predicate is true for.
static ClassTransformPREVIEW	endHandler(Consumer<ClassBuilderPREVIEW> finisher)	Create a class transform that passes each element through to the builder, and calls the specified function when transformation is complete.
static ClassTransformPREVIEW	ofStateful(Supplier<ClassTransformPREVIEW> supplier)	Create a stateful class transform from a Supplier.
default ClassFileTransform.ResolvedTransformPREVIEW<ClassElementPREVIEW>	resolve(ClassBuilderPREVIEW builder)	Bind a transform to a builder.
static ClassTransformPREVIEW	transformingFields(FieldTransformPREVIEW xform)	Create a class transform that transforms FieldModelPREVIEW elements with the supplied field transform.
static ClassTransformPREVIEW	transformingMethodBodies(CodeTransformPREVIEW xform)	Create a class transform that transforms the CodeAttributePREVIEW (method body) of MethodModelPREVIEW elements with the supplied code transform.
static ClassTransformPREVIEW	transformingMethodBodies(Predicate<MethodModelPREVIEW> filter, CodeTransformPREVIEW xform)	Create a class transform that transforms the CodeAttributePREVIEW (method body) of MethodModelPREVIEW elements with the supplied code transform.
static ClassTransformPREVIEW	transformingMethods(MethodTransformPREVIEW xform)	Create a class transform that transforms MethodModelPREVIEW elements with the supplied method transform.
static ClassTransformPREVIEW	transformingMethods(Predicate<MethodModelPREVIEW> filter, MethodTransformPREVIEW xform)	Create a class transform that transforms MethodModelPREVIEW elements with the supplied method transform.

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

accept, atEnd, atStart

Field Details

ACCEPT_ALL

static final ClassTransformPREVIEW ACCEPT_ALL

A class transform that sends all elements to the builder.

Method Details

ofStateful

static ClassTransformPREVIEW ofStateful(Supplier<ClassTransformPREVIEW> supplier)

Create a stateful class transform from a Supplier. The supplier will be invoked for each transformation.

Parameters:

supplier - a Supplier that produces a fresh transform object for each traversal

Returns:

the stateful class transform

endHandler

static ClassTransformPREVIEW endHandler(Consumer<ClassBuilderPREVIEW> finisher)

Create a class transform that passes each element through to the builder, and calls the specified function when transformation is complete.

Parameters:

finisher - the function to call when transformation is complete

Returns:

the class transform

dropping

static ClassTransformPREVIEW dropping(Predicate<ClassElementPREVIEW> filter)

Create a class transform that passes each element through to the builder, except for those that the supplied Predicate is true for.

Parameters:

filter - the predicate that determines which elements to drop

Returns:

the class transform

transformingMethods

static ClassTransformPREVIEW transformingMethods(Predicate<MethodModelPREVIEW> filter,
 MethodTransformPREVIEW xform)

Create a class transform that transforms MethodModel^PREVIEW elements with the supplied method transform.

Parameters:

filter - a predicate that determines which methods to transform

xform - the method transform

Returns:

the class transform

transformingMethods

static ClassTransformPREVIEW transformingMethods(MethodTransformPREVIEW xform)

Create a class transform that transforms MethodModel^PREVIEW elements with the supplied method transform.

Parameters:

xform - the method transform

Returns:

the class transform

transformingMethodBodies

static ClassTransformPREVIEW transformingMethodBodies(Predicate<MethodModelPREVIEW> filter,
 CodeTransformPREVIEW xform)

Create a class transform that transforms the CodeAttribute^PREVIEW (method body) of MethodModel^PREVIEW elements with the supplied code transform.

Parameters:

filter - a predicate that determines which methods to transform

xform - the code transform

Returns:

the class transform

transformingMethodBodies

static ClassTransformPREVIEW transformingMethodBodies(CodeTransformPREVIEW xform)

Create a class transform that transforms the CodeAttribute^PREVIEW (method body) of MethodModel^PREVIEW elements with the supplied code transform.

Parameters:

xform - the code transform

Returns:

the class transform

transformingFields

static ClassTransformPREVIEW transformingFields(FieldTransformPREVIEW xform)

Create a class transform that transforms FieldModel^PREVIEW elements with the supplied field transform.

Parameters:

xform - the field transform

Returns:

the class transform

andThen

default ClassTransformPREVIEW andThen(ClassTransformPREVIEW t)

Description copied from interface: ClassFileTransform

Chain this transform with another; elements presented to the builder of this transform will become the input to the next transform.

Specified by:

andThen in interface ClassFileTransformPREVIEW<ClassTransformPREVIEW,ClassElementPREVIEW,ClassBuilderPREVIEW>

Implementation Requirements:

The default implementation returns this class transform chained with another class transform from the argument. Chaining of two transforms requires to involve a chained builder serving as a target builder for this transform and also as a source of elements for the downstream transform.

Parameters:

t - the downstream transform

Returns:

the chained transform

resolve

default ClassFileTransform.ResolvedTransformPREVIEW<ClassElementPREVIEW> resolve(ClassBuilderPREVIEW builder)

Description copied from interface: ClassFileTransform

Bind a transform to a builder. If the transform is chained, intermediate builders are created for each chain link. If the transform is stateful (see, e.g., ofStateful(Supplier)), the supplier is invoked to get a fresh transform object.

This method is a low-level method that should rarely be used by user code; most of the time, user code should prefer ClassFileBuilder.transform(CompoundElement, ClassFileTransform)^PREVIEW, which resolves the transform and executes it on the current builder.

Specified by:

resolve in interface ClassFileTransformPREVIEW<ClassTransformPREVIEW,ClassElementPREVIEW,ClassBuilderPREVIEW>

Implementation Requirements:

The default implementation returns a resolved transform bound to the given class builder.

Parameters:

builder - the builder to bind to

Returns:

the bound result