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:

  • 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:

    • 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:

  • 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