8260517: implement Sealed Classes as a standard feature in Java

Co-authored-by: Harold Seigel <hseigel@openjdk.org> Co-authored-by: Vicente Romero <vromero@openjdk.org> Reviewed-by: dholmes, mcimadamore, jlahoda
openjdk · May 20, 2021 · 0fa9223 · 0fa9223 · openjdk-notifier · May 20, 2021
1 parent 31b98e1
commit 0fa9223
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Showing 54 changed files with 169 additions and 393 deletions.
diff --git a/make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java b/make/langtools/src/classes/build/tools/symbolgenerator/CreateSymbols.java
@@ -132,6 +132,7 @@
 import com.sun.tools.classfile.Module_attribute.RequiresEntry;
 import com.sun.tools.classfile.NestHost_attribute;
 import com.sun.tools.classfile.NestMembers_attribute;
+import com.sun.tools.classfile.PermittedSubclasses_attribute;
 import com.sun.tools.classfile.Record_attribute;
 import com.sun.tools.classfile.Record_attribute.ComponentInfo;
 import com.sun.tools.classfile.RuntimeAnnotations_attribute;
@@ -978,6 +979,16 @@ private void addAttributes(ClassHeaderDescription header,
  attributes.put(Attribute.Record,
  new Record_attribute(attributeString, recordComponents));
  }
+ if (header.isSealed) {
+ int attributeString = addString(constantPool, Attribute.PermittedSubclasses);
+ int[] subclasses = new int[header.permittedSubclasses.size()];
+ int i = 0;
+ for (String intf : header.permittedSubclasses) {
+ subclasses[i++] = addClass(constantPool, intf);
+ }
+ attributes.put(Attribute.PermittedSubclasses,
+ new PermittedSubclasses_attribute(attributeString, subclasses));
+ }
  addInnerClassesAttribute(header, constantPool, attributes);
  }
 
@@ -2229,6 +2240,16 @@ private boolean readAttribute(ClassFile cf, FeatureDescription feature, Attribut
  }
  break;
  }
+ case Attribute.PermittedSubclasses: {
+ assert feature instanceof ClassHeaderDescription;
+ PermittedSubclasses_attribute permittedSubclasses = (PermittedSubclasses_attribute) attr;
+ ClassHeaderDescription chd = (ClassHeaderDescription) feature;
+ chd.permittedSubclasses = Arrays.stream(permittedSubclasses.subtypes)
+ .mapToObj(i -> getClassName(cf, i))
+ .collect(Collectors.toList());
+ chd.isSealed = true;
+ break;
+ }
  default:
  throw new IllegalStateException("Unhandled attribute: " +
  attrName);
@@ -3077,6 +3098,8 @@ static class ClassHeaderDescription extends HeaderDescription {
  List<String> nestMembers;
  boolean isRecord;
  List<RecordComponentDescription> recordComponents;
+ boolean isSealed;
+ List<String> permittedSubclasses;
 
  @Override
  public int hashCode() {
@@ -3087,6 +3110,8 @@ public int hashCode() {
  hash = 17 * hash + Objects.hashCode(this.nestMembers);
  hash = 17 * hash + Objects.hashCode(this.isRecord);
  hash = 17 * hash + Objects.hashCode(this.recordComponents);
+ hash = 17 * hash + Objects.hashCode(this.isSealed);
+ hash = 17 * hash + Objects.hashCode(this.permittedSubclasses);
  return hash;
  }
 
@@ -3117,6 +3142,12 @@ public boolean equals(Object obj) {
  if (!listEquals(this.recordComponents, other.recordComponents)) {
  return false;
  }
+ if (this.isSealed != other.isSealed) {
+ return false;
+ }
+ if (!listEquals(this.permittedSubclasses, other.permittedSubclasses)) {
+ return false;
+ }
  return true;
  }
 
@@ -3137,6 +3168,9 @@ public void write(Appendable output, String baselineVersion, String version) thr
  if (isRecord) {
  output.append(" record true");
  }
+ if (isSealed) {
+ output.append(" sealed true");
+ }
  writeAttributes(output);
  output.append("\n");
  writeRecordComponents(output, baselineVersion, version);
@@ -3163,6 +3197,11 @@ public boolean read(LineBasedReader reader) throws IOException {
  readRecordComponents(reader);
  }
  readInnerClasses(reader);
+ isSealed = reader.attributes.containsKey("permittedSubclasses");
+ if (isSealed) {
+ String subclassesList = reader.attributes.get("permittedSubclasses");
+ permittedSubclasses = deserializeList(subclassesList);
+ }
 
  return true;
  }

diff --git a/src/hotspot/share/classfile/classFileParser.cpp b/src/hotspot/share/classfile/classFileParser.cpp
@@ -3532,12 +3532,6 @@ void ClassFileParser::parse_classfile_bootstrap_methods_attribute(const ClassFil
  CHECK);
 }
 
-bool ClassFileParser::supports_sealed_types() {
- return _major_version == JVM_CLASSFILE_MAJOR_VERSION &&
- _minor_version == JAVA_PREVIEW_MINOR_VERSION &&
- Arguments::enable_preview();
-}
-
 void ClassFileParser::parse_classfile_attributes(const ClassFileStream* const cfs,
  ConstantPool* cp,
  ClassFileParser::ClassAnnotationCollector* parsed_annotations,
@@ -3794,8 +3788,8 @@ void ClassFileParser::parse_classfile_attributes(const ClassFileStream* const cf
  parsed_record_attribute = true;
  record_attribute_start = cfs->current();
  record_attribute_length = attribute_length;
- } else if (tag == vmSymbols::tag_permitted_subclasses()) {
- if (supports_sealed_types()) {
+ } else if (_major_version >= JAVA_17_VERSION) {
+ if (tag == vmSymbols::tag_permitted_subclasses()) {
  if (parsed_permitted_subclasses_attribute) {
  classfile_parse_error("Multiple PermittedSubclasses attributes in class file %s", CHECK);
  return;
@@ -3810,7 +3804,7 @@ void ClassFileParser::parse_classfile_attributes(const ClassFileStream* const cf
  permitted_subclasses_attribute_length = attribute_length;
  }
  }
- // Skip attribute_length for any attribute where major_verson >= JAVA_16_VERSION
+ // Skip attribute_length for any attribute where major_verson >= JAVA_17_VERSION
  cfs->skip_u1(attribute_length, CHECK);
  } else {
  // Unknown attribute

diff --git a/src/hotspot/share/classfile/classFileParser.hpp b/src/hotspot/share/classfile/classFileParser.hpp
@@ -333,9 +333,6 @@ class ClassFileParser {
  const u1* const record_attribute_start,
  TRAPS);
 
- bool supports_sealed_types();
- bool supports_records();
-
  void parse_classfile_attributes(const ClassFileStream* const cfs,
  ConstantPool* cp,
  ClassAnnotationCollector* parsed_annotations,

diff --git a/src/hotspot/share/include/jvm.h b/src/hotspot/share/include/jvm.h
@@ -606,15 +606,15 @@ JVM_GetNestHost(JNIEnv *env, jclass current);
 JNIEXPORT jobjectArray JNICALL
 JVM_GetNestMembers(JNIEnv *env, jclass current);
 
-/* Records - since JDK 14 */
+/* Records - since JDK 16 */
 
 JNIEXPORT jboolean JNICALL
 JVM_IsRecord(JNIEnv *env, jclass cls);
 
 JNIEXPORT jobjectArray JNICALL
 JVM_GetRecordComponents(JNIEnv *env, jclass ofClass);
 
-/* Sealed types - since JDK 15 */
+/* Sealed classes - since JDK 17 */
 
 JNIEXPORT jobjectArray JNICALL
 JVM_GetPermittedSubclasses(JNIEnv *env, jclass current);

diff --git a/src/java.base/share/classes/java/lang/Class.java b/src/java.base/share/classes/java/lang/Class.java
@@ -4475,9 +4475,8 @@ public Optional<ClassDesc> describeConstable() {
  *
  * @jls 8.1 Class Declarations
  * @jls 9.1 Interface Declarations
- * @since 15
+ * @since 17
  */
- @jdk.internal.javac.PreviewFeature(feature=jdk.internal.javac.PreviewFeature.Feature.SEALED_CLASSES, reflective=true)
  @CallerSensitive
  public Class<?>[] getPermittedSubclasses() {
  Class<?>[] subClasses;
@@ -4524,14 +4523,13 @@ private boolean isDirectSubType(Class<?> c) {
  * subclasses; {@link #getPermittedSubclasses()} returns a non-null but
  * possibly empty value for a sealed class or interface.
  *
- * @return {@code true} if and only if this {@code Class} object represents a sealed class or interface.
+ * @return {@code true} if and only if this {@code Class} object represents
+ * a sealed class or interface.
  *
  * @jls 8.1 Class Declarations
  * @jls 9.1 Interface Declarations
- * @since 15
+ * @since 17
  */
- @jdk.internal.javac.PreviewFeature(feature=jdk.internal.javac.PreviewFeature.Feature.SEALED_CLASSES, reflective=true)
- @SuppressWarnings("preview")
  public boolean isSealed() {
  if (isArray() || isPrimitive()) {
  return false;

diff --git a/src/java.base/share/classes/jdk/internal/javac/PreviewFeature.java b/src/java.base/share/classes/jdk/internal/javac/PreviewFeature.java
@@ -54,6 +54,9 @@
  public boolean reflective() default false;
 
  public enum Feature {
+ /*
+ * This one can only be removed after JDK 17
+ */
  SEALED_CLASSES,
  /**
  * A key for testing.

diff --git a/src/jdk.compiler/share/classes/com/sun/source/tree/ClassTree.java b/src/jdk.compiler/share/classes/com/sun/source/tree/ClassTree.java
@@ -93,10 +93,8 @@ public interface ClassTree extends StatementTree {
  *
  * @return the subclasses
  *
- * @since 15
+ * @since 17
  */
- @jdk.internal.javac.PreviewFeature(feature=jdk.internal.javac.PreviewFeature.Feature.SEALED_CLASSES,
- reflective=true)
  default List<? extends Tree> getPermitsClause() {
  return List.of();
  }

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Preview.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Preview.java
@@ -183,8 +183,6 @@ public boolean isEnabled() {
  */
  public boolean isPreview(Feature feature) {
  return switch (feature) {
- case SEALED_CLASSES -> true;
-
  //Note: this is a backdoor which allows to optionally treat all features as 'preview' (for testing).
  //When real preview features will be added, this method can be implemented to return 'true'
  //for those selected features, and 'false' for all the others.
@@ -224,9 +222,7 @@ public Error disabledError(JavaFileObject classfile, int majorVersion) {
  * @return true iff sym has been declared using a preview language feature
  */
  public boolean declaredUsingPreviewFeature(Symbol sym) {
- return ((sym.flags() & RECORD) != 0 && isPreview(Feature.RECORDS)) ||
- ((sym.flags() & SEALED) != 0 && isPreview(Feature.SEALED_CLASSES)) ||
- ((sym.flags() & NON_SEALED) != 0 && isPreview(Feature.SEALED_CLASSES));
+ return false;
  }
 
  /**

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Check.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Check.java
@@ -161,8 +161,7 @@ protected Check(Context context) {
  deferredLintHandler = DeferredLintHandler.instance(context);
 
  allowRecords = Feature.RECORDS.allowedInSource(source);
- allowSealed = (!preview.isPreview(Feature.SEALED_CLASSES) || preview.isEnabled()) &&
- Feature.SEALED_CLASSES.allowedInSource(source);
+ allowSealed = Feature.SEALED_CLASSES.allowedInSource(source);
  }
 
  /** Character for synthetic names

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassReader.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassReader.java
@@ -278,8 +278,7 @@ protected ClassReader(Context context) {
  preview = Preview.instance(context);
  allowModules = Feature.MODULES.allowedInSource(source);
  allowRecords = Feature.RECORDS.allowedInSource(source);
- allowSealedTypes = (!preview.isPreview(Feature.SEALED_CLASSES) || preview.isEnabled()) &&
- Feature.SEALED_CLASSES.allowedInSource(source);
+ allowSealedTypes = Feature.SEALED_CLASSES.allowedInSource(source);
 
  saveParameterNames = options.isSet(PARAMETERS);
 

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java
@@ -186,8 +186,7 @@ protected JavacParser(ParserFactory fac,
  this.allowYieldStatement = (!preview.isPreview(Feature.SWITCH_EXPRESSION) || preview.isEnabled()) &&
  Feature.SWITCH_EXPRESSION.allowedInSource(source);
  this.allowRecords = Feature.RECORDS.allowedInSource(source);
- this.allowSealedTypes = (!preview.isPreview(Feature.SEALED_CLASSES) || preview.isEnabled()) &&
- Feature.SEALED_CLASSES.allowedInSource(source);
+ this.allowSealedTypes = Feature.SEALED_CLASSES.allowedInSource(source);
  }
 
  protected AbstractEndPosTable newEndPosTable(boolean keepEndPositions) {

diff --git a/test/hotspot/jtreg/runtime/modules/SealedInterfaceModuleTest.java b/test/hotspot/jtreg/runtime/modules/SealedInterfaceModuleTest.java
@@ -27,11 +27,11 @@
  * @modules java.base/jdk.internal.misc
  * @library /test/lib ..
  * @compile sealedP1/SuperInterface.jcod
- * @compile --enable-preview --source ${jdk.version} sealedP1/C1.java sealedP2/C2.java sealedP3/C3.java
+ * @compile sealedP1/C1.java sealedP2/C2.java sealedP3/C3.java
  * @build sun.hotspot.WhiteBox
  * @compile/module=java.base java/lang/ModuleHelper.java
  * @run driver jdk.test.lib.helpers.ClassFileInstaller sun.hotspot.WhiteBox
- * @run main/othervm -Xbootclasspath/a:. --enable-preview -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI SealedInterfaceModuleTest
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI SealedInterfaceModuleTest
  */
 
 public class SealedInterfaceModuleTest {

diff --git a/test/hotspot/jtreg/runtime/modules/SealedModuleTest.java b/test/hotspot/jtreg/runtime/modules/SealedModuleTest.java
@@ -27,11 +27,11 @@
  * @modules java.base/jdk.internal.misc
  * @library /test/lib ..
  * @compile sealedP1/SuperClass.jcod
- * @compile --enable-preview --source ${jdk.version} sealedP1/C1.java sealedP2/C2.java sealedP3/C3.java
+ * @compile sealedP1/C1.java sealedP2/C2.java sealedP3/C3.java
  * @build sun.hotspot.WhiteBox
  * @compile/module=java.base java/lang/ModuleHelper.java
  * @run driver jdk.test.lib.helpers.ClassFileInstaller sun.hotspot.WhiteBox
- * @run main/othervm -Xbootclasspath/a:. --enable-preview -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI SealedModuleTest
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI SealedModuleTest
  */
 
 public class SealedModuleTest {

diff --git a/test/hotspot/jtreg/runtime/modules/sealedP1/SuperClass.jcod b/test/hotspot/jtreg/runtime/modules/sealedP1/SuperClass.jcod
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@
 
 class sealedP1/SuperClass {
  0xCAFEBABE;
- 65535; // minor version
+ 0; // minor version
  61; // version
  [20] { // Constant Pool
  ; // first element is empty

diff --git a/test/hotspot/jtreg/runtime/modules/sealedP1/SuperInterface.jcod b/test/hotspot/jtreg/runtime/modules/sealedP1/SuperInterface.jcod
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,7 +32,7 @@
 //
 class sealedP1/SuperInterface {
  0xCAFEBABE;
- 65535; // minor version
+ 0; // minor version
  61; // version
  [14] { // Constant Pool
  ; // first element is empty

diff --git a/test/hotspot/jtreg/runtime/sealedClasses/AbstractSealedTest.java b/test/hotspot/jtreg/runtime/sealedClasses/AbstractSealedTest.java