Enum Class ClassFile.ConstantPoolSharingOption

java.lang.Object

java.lang.Enum<ClassFile.ConstantPoolSharingOption>

java.lang.classfile.ClassFile.ConstantPoolSharingOption

All Implemented Interfaces:

Serializable, ClassFile.Option, Comparable<ClassFile.ConstantPoolSharingOption>, Constable

Enclosing interface:

ClassFile

public static enum ClassFile.ConstantPoolSharingOption
extends Enum<ClassFile.ConstantPoolSharingOption>
implements ClassFile.Option

Option describing whether to extend from the original constant pool when transforming a class file. The default is SHARED_POOL to extend from the original constant pool.

This option affects all overloads of transformClass. Extending from the original constant pool keeps the indices into the constant pool intact, which enables significant optimizations in processing time and minimizes differences between the original and transformed class files, but may result in a bigger transformed class file when many elements of the original class file are dropped and many original constant pool entries become unused.

An alternative to this option is to use ClassFile.build(ClassEntry, ConstantPoolBuilder, Consumer) directly. It allows extension from arbitrary constant pools, and may be useful if a built class file reuses structures from multiple original class files.

Since:

24

See Also:

• ConstantPoolBuilder
• ClassFile.build(ClassEntry, ConstantPoolBuilder, Consumer)
• ClassFile.transformClass(ClassModel, ClassTransform)

Nested Class Summary

Nested classes/interfaces declared in class Enum

Enum.EnumDesc<E>

Modifier and Type	Class	Description
static final class	Enum.EnumDesc<E extends Enum<E>>	A nominal descriptor for an enum constant.

Enum Constant Summary

Enum Constants

Enum Constant	Description
NEW_POOL	Creates a new constant pool when transforming the class file.
SHARED_POOL	Extend the new constant pool from the original constant pool when transforming the class file.

Method Summary

Modifier and Type	Method	Description
static ClassFile.ConstantPoolSharingOption	valueOf(String name)	Returns the enum constant of this class with the specified name.
static ClassFile.ConstantPoolSharingOption[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods declared in class Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Modifier and Type	Method	Description
protected final Object	clone()	Throws CloneNotSupportedException.
final int	compareTo(ClassFile.ConstantPoolSharingOption o)	Compares this enum with the specified object for order.
final Optional<Enum.EnumDesc<ClassFile.ConstantPoolSharingOption>>	describeConstable()	Returns an enum descriptor EnumDesc for this instance, if one can be constructed, or an empty Optional if one cannot be.
final boolean	equals(Object other)	Returns true if the specified object is equal to this enum constant.
protected final void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. Finalization has been deprecated for removal.
final Class<ClassFile.ConstantPoolSharingOption>	getDeclaringClass()	Returns the Class object corresponding to this enum constant's enum type.
final int	hashCode()	Returns a hash code for this enum constant.
final String	name()	Returns the name of this enum constant, exactly as declared in its enum declaration.
final int	ordinal()	Returns the ordinal of this enumeration constant (its position in its enum declaration, where the initial constant is assigned an ordinal of zero).
String	toString()	Returns the name of this enum constant, as contained in the declaration.
static <T extends Enum<T>> T	valueOf(Class<T> enumClass, String name)	Returns the enum constant of the specified enum class with the specified name.

Methods declared in class Object

getClass, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
final Class<?>	getClass()	Returns the runtime class of this Object.
final void	notify()	Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll()	Wakes up all threads that are waiting on this object's monitor.
final void	wait()	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
final void	wait(long timeoutMillis)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
final void	wait(long timeoutMillis, int nanos)	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Enum Constant Details

SHARED_POOL

public static final ClassFile.ConstantPoolSharingOption SHARED_POOL

Extend the new constant pool from the original constant pool when transforming the class file.

These two transformations below are equivalent:

ClassModel originalClass = ...
ClassDesc resultClassName = ...
ClassTransform classTransform = ...
var resultOne = ClassFile.of(ConstantPoolSharingOption.SHARED_POOL)
        .transformClass(originalClass, resultClassName, classTransform);
var resultTwo = ClassFile.of().build(resultClassName, ConstantPoolBuilder.of(originalClass),
        clb -> clb.transform(originalClass, classTransform));

See Also:

• ConstantPoolBuilder::of(ClassModel)

NEW_POOL

public static final ClassFile.ConstantPoolSharingOption NEW_POOL

Creates a new constant pool when transforming the class file.

These two transformations below are equivalent:

ClassModel originalClass = ...
ClassDesc resultClassName = ...
ClassTransform classTransform = ...
var resultOne = ClassFile.of(ConstantPoolSharingOption.NEW_POOL)
        .transformClass(originalClass, resultClassName, classTransform);
var resultTwo = ClassFile.of().build(resultClassName, ConstantPoolBuilder.of(),
        clb -> clb.transform(originalClass, classTransform));

See Also:

• ConstantPoolBuilder::of()

Method Details

values

public static ClassFile.ConstantPoolSharingOption[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static ClassFile.ConstantPoolSharingOption valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null