Summary

Remove Optional<XxxModel> original() from ClassBuilder, MethodBuilder, FieldBuilder, CodeBuilder. Make Optional<XxxModel> parent() return present if and only if the model is an immutable read model (instead of a wip transforming model)

Problem

The original method in the builders are not useful. They are useful only to transforms, but most ad-hoc transforms go through transformXxx which has access to the original model. The ClassFileBuilder::transform has the same functionality of transforming an "original" model with a transform, but the called builder does not have an "original" model as a result, further increasing the confusion.

The parent() method allows easy access to the parents of models, such as methods or fields from a class model. However, it currently returns the original class model for a transformed buffered field or method (but not code), which is erroneous as those models can't be found in the class by iteration.

Solution

Remove the original() methods; they have no usages. Make the parent() methods only return present value if the model is bound and not partially transformed ("buffered"), that it can be discovered on the parent model by compound element component iteration.

Specification

No specification change for parent(). For original():

diff --git a/src/java.base/share/classes/java/lang/classfile/ClassBuilder.java b/src/java.base/share/classes/java/lang/classfile/ClassBuilder.java
index f1b8bb13d27..a55b93e7c07 100644
--- a/src/java.base/share/classes/java/lang/classfile/ClassBuilder.java
+++ b/src/java.base/share/classes/java/lang/classfile/ClassBuilder.java
@@ -58,12 +57,6 @@ public sealed interface ClassBuilder
         extends ClassFileBuilder<ClassElement, ClassBuilder>
         permits ChainedClassBuilder, DirectClassBuilder {

-    /**
-     * {@return the {@link ClassModel} representing the class being transformed,
-     * if this class builder represents the transformation of some {@link ClassModel}}
-     */
-    Optional<ClassModel> original();
-
     /**
      * Sets the classfile version.
      * @param major the major version number
diff --git a/src/java.base/share/classes/java/lang/classfile/CodeBuilder.java b/src/java.base/share/classes/java/lang/classfile/CodeBuilder.java
index a1666375091..a6ec41cc437 100644
--- a/src/java.base/share/classes/java/lang/classfile/CodeBuilder.java
+++ b/src/java.base/share/classes/java/lang/classfile/CodeBuilder.java
@@ -127,12 +127,6 @@ public sealed interface CodeBuilder
         extends ClassFileBuilder<CodeElement, CodeBuilder>
         permits CodeBuilder.BlockCodeBuilder, ChainedCodeBuilder, TerminalCodeBuilder, NonterminalCodeBuilder {

-    /**
-     * {@return the {@link CodeModel} representing the method body being transformed,
-     * if this code builder represents the transformation of some {@link CodeModel}}
-     */
-    Optional<CodeModel> original();
-
     /** {@return a fresh unbound label} */
     Label newLabel();

diff --git a/src/java.base/share/classes/java/lang/classfile/FieldBuilder.java b/src/java.base/share/classes/java/lang/classfile/FieldBuilder.java
index 18a598398ec..c0e733676f7 100644
--- a/src/java.base/share/classes/java/lang/classfile/FieldBuilder.java
+++ b/src/java.base/share/classes/java/lang/classfile/FieldBuilder.java
@@ -68,9 +67,4 @@ default FieldBuilder withFlags(AccessFlag... flags) {
         return with(AccessFlags.ofField(flags));
     }

-    /**
-     * {@return the {@link FieldModel} representing the field being transformed,
-     * if this field builder represents the transformation of some {@link FieldModel}}
-     */
-    Optional<FieldModel> original();
 }
diff --git a/src/java.base/share/classes/java/lang/classfile/MethodBuilder.java b/src/java.base/share/classes/java/lang/classfile/MethodBuilder.java
index ece292c361b..4cf34c95ed0 100644
--- a/src/java.base/share/classes/java/lang/classfile/MethodBuilder.java
+++ b/src/java.base/share/classes/java/lang/classfile/MethodBuilder.java
@@ -50,12 +49,6 @@ public sealed interface MethodBuilder
         extends ClassFileBuilder<MethodElement, MethodBuilder>
         permits ChainedMethodBuilder, TerminalMethodBuilder {

-    /**
-     * {@return the {@link MethodModel} representing the method being transformed,
-     * if this method builder represents the transformation of some {@link MethodModel}}
-     */
-    Optional<MethodModel> original();
-
     /**
      * Sets the method access flags.
      * @param flags the access flags, as a bit mask