8312418: Add Elements.getEnumConstantBody

Co-authored-by: Jan Lahoda <jlahoda@openjdk.org>
Reviewed-by: vromero
This commit is contained in:
Joe Darcy 2023-09-08 22:06:24 +00:00
parent dccf670492
commit 578ded4645
4 changed files with 340 additions and 1 deletions
src
java.compiler/share/classes/javax/lang/model/util
jdk.compiler/share/classes/com/sun/tools/javac
test/langtools/tools/javac/processing/model/util/elements

@ -758,6 +758,29 @@ public interface Elements {
return false;
}
/**
* {@return the class body of an {@code enum} constant if the
* argument is an {@code enum} constant declared with an optional
* class body, {@code null} otherwise}
*
* @implSpec
* The default implementation of this method throws {@code
* UnsupportedOperationException} if the argument is an {@code
* enum} constant and throws an {@code IllegalArgumentException}
* if it is not.
*
* @param enumConstant an enum constant
* @throws IllegalArgumentException if the argument is not an {@code enum} constant
* @jls 8.9.1 Enum Constants
* @since 22
*/
default TypeElement getEnumConstantBody(VariableElement enumConstant) {
switch(enumConstant.getKind()) {
case ENUM_CONSTANT -> throw new UnsupportedOperationException();
default -> throw new IllegalArgumentException("Argument not an enum constant");
}
}
/**
* Returns the record component for the given accessor. Returns
* {@code null} if the given method is not a record component

@ -71,6 +71,7 @@ import com.sun.tools.javac.util.Name;
import static com.sun.tools.javac.code.Kinds.Kind.*;
import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
import static com.sun.tools.javac.code.TypeTag.CLASS;
import com.sun.tools.javac.comp.Attr;
import com.sun.tools.javac.comp.Modules;
import com.sun.tools.javac.comp.Resolve;
import com.sun.tools.javac.comp.Resolve.RecoveryLoadClass;
@ -93,6 +94,7 @@ public class JavacElements implements Elements {
private final Names names;
private final Types types;
private final Enter enter;
private final Attr attr;
private final Resolve resolve;
private final JavacTaskImpl javacTaskImpl;
private final Log log;
@ -114,6 +116,7 @@ public class JavacElements implements Elements {
names = Names.instance(context);
types = Types.instance(context);
enter = Enter.instance(context);
attr = Attr.instance(context);
resolve = Resolve.instance(context);
JavacTask t = context.get(JavacTask.class);
javacTaskImpl = t instanceof JavacTaskImpl taskImpl ? taskImpl : null;
@ -725,6 +728,37 @@ public class JavacElements implements Elements {
return (msym.flags() & Flags.AUTOMATIC_MODULE) != 0;
}
@Override @DefinedBy(Api.LANGUAGE_MODEL)
public TypeElement getEnumConstantBody(VariableElement enumConstant) {
if (enumConstant.getKind() == ElementKind.ENUM_CONSTANT) {
JCTree enumBodyTree = getTreeAlt(enumConstant);
JCTree enclosingEnumTree = getTreeAlt(enumConstant.getEnclosingElement());
if (enumBodyTree instanceof JCVariableDecl decl
&& enclosingEnumTree instanceof JCClassDecl clazz
&& decl.init instanceof JCNewClass nc
&& nc.def != null) {
if ((clazz.sym.flags_field & Flags.UNATTRIBUTED) != 0) {
attr.attribClass(clazz.pos(), clazz.sym);
}
return nc.def.sym; // ClassSymbol for enum constant body
} else {
return null;
}
} else {
throw new IllegalArgumentException("Argument not an enum constant");
}
}
private JCTree getTreeAlt(Element e) {
Symbol sym = cast(Symbol.class, e);
Env<AttrContext> enterEnv = getEnterEnv(sym);
if (enterEnv == null)
return null;
JCTree tree = TreeInfo.declarationFor(sym, enterEnv.tree);
return tree;
}
@Override @DefinedBy(Api.LANGUAGE_MODEL)
public boolean isCompactConstructor(ExecutableElement e) {
return (((MethodSymbol)e).flags() & Flags.COMPACT_RECORD_CONSTRUCTOR) != 0;

@ -1,5 +1,5 @@
/*
* Copyright (c) 2005, 2021, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2005, 2023, 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
@ -184,6 +184,16 @@ public class PrintingProcessor extends AbstractProcessor {
NestingKind nestingKind = e.getNestingKind();
if (NestingKind.ANONYMOUS == nestingKind) {
// Print nothing for an anonymous class used for an
// enum constant body.
TypeMirror supertype = e.getSuperclass();
if (supertype.getKind() != TypeKind.NONE) {
TypeElement superClass = (TypeElement)(((DeclaredType)supertype).asElement());
if (superClass.getKind() == ENUM) {
return this;
}
}
// Print out an anonymous class in the style of a
// class instance creation expression rather than a
// class declaration.
@ -693,6 +703,12 @@ public class PrintingProcessor extends AbstractProcessor {
}
private void printPermittedSubclasses(TypeElement e) {
if (e.getKind() == ENUM) {
// any permitted classes on an enum are anonymous
// classes for enum bodies, elide.
return;
}
List<? extends TypeMirror> subtypes = e.getPermittedSubclasses();
if (!subtypes.isEmpty()) { // could remove this check with more complicated joining call
writer.print(" permits ");

@ -0,0 +1,266 @@
/*
* Copyright (c) 2023, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8312418
* @summary Test Elements.getEnumConstantBody
* @library /tools/javac/lib
* @build JavacTestingAbstractProcessor TestGetEnumConstantBody
* @compile -processor TestGetEnumConstantBody -XDshould.stop-at=FLOW TestGetEnumConstantBody.java
*/
import java.io.IOException;
import java.io.Writer;
import java.util.*;
import java.util.function.*;
import javax.annotation.processing.*;
import javax.lang.model.element.*;
import javax.lang.model.util.*;
import javax.lang.model.type.*;
/**
* Test basic workings of Elements.getEnumConstantBody
*/
public class TestGetEnumConstantBody extends JavacTestingAbstractProcessor {
private Elements vacuousElements = new VacuousElements();
private Set<Element> allElements = new HashSet<>();
private int round;
public boolean process(Set<? extends TypeElement> annotations,
RoundEnvironment roundEnv) {
allElements.addAll(roundEnv.getRootElements());
// In the innermost loop, examine the fields defined by the the nested classes
for (TypeElement typeRoot : ElementFilter.typesIn(allElements) ) {
if (typeRoot.getQualifiedName().contentEquals("Gen")) {
continue;
}
boolean elementSeen = false;
for (TypeElement typeElt : ElementFilter.typesIn(typeRoot.getEnclosedElements()) ) {
System.out.println("Testing type " + typeElt);
for (VariableElement field : ElementFilter.fieldsIn(typeElt.getEnclosedElements()) ) {
elementSeen = true;
System.out.println(field);
switch (field.getKind()) {
case FIELD -> expectIAE(field);
case ENUM_CONSTANT -> testEnumConstant(field, typeElt);
default -> throw new RuntimeException("Unexpected field kind seen");
}
}
}
if (!elementSeen) {
throw new RuntimeException("No elements seen.");
}
}
switch (round++) {
case 0:
try (Writer w = processingEnv.getFiler().createSourceFile("Cleaned").openWriter()) {
w.write("""
class Enclosing {
enum Cleaned {
@TestGetEnumConstantBody.ExpectedBinaryName("Enclosing$Cleaned$2")
A(new Object() {}) {
void test(Gen g) {
g.run();
}
},
B,
@TestGetEnumConstantBody.ExpectedBinaryName("Enclosing$Cleaned$4")
C(new Object() {}) {
};
private Cleaned() {}
private Cleaned(Object o) {}
}
}
""");
} catch (IOException ex) {
throw new RuntimeException(ex);
}
break;
case 1:
try (Writer w = processingEnv.getFiler().createSourceFile("Gen").openWriter()) {
w.write("""
public class Gen {
public void run() {}
}
""");
} catch (IOException ex) {
throw new RuntimeException(ex);
}
break;
}
return true;
}
private String computeExpectedBinaryName(VariableElement e) {
ExpectedBinaryName ebn = e.getAnnotation(ExpectedBinaryName.class);
return (ebn == null) ? null : ebn.value();
}
private void expectIAE(VariableElement variable) {
expectException0(() -> elements.getEnumConstantBody(variable),
"Expected exception not thrown");
expectException0(() -> vacuousElements.getEnumConstantBody(variable),
"Expected vacuous exception not thrown");
}
private void expectException0(Supplier<TypeElement> supplier, String message) {
try {
var typeElement = supplier.get();
messager.printError(message, typeElement);
} catch (IllegalArgumentException iae) {
; // Expected
}
}
void expectUOE(VariableElement field) {
try {
var result = vacuousElements.getEnumConstantBody(field);
messager.printError("Unexpected non-exceptional result returned", field);
} catch(UnsupportedOperationException uoe) {
; // Expected
}
}
private void testEnumConstant(VariableElement field,
TypeElement enclosingClass) {
String expectedBinaryName = computeExpectedBinaryName(field);
boolean expectEnumConstantBody = expectedBinaryName != null;
System.out.println("\tTesting enum constant " + field + " expected " + expectEnumConstantBody);
expectUOE(field);
TypeElement enumConstantBody = elements.getEnumConstantBody(field);
if (Objects.nonNull(enumConstantBody) != expectEnumConstantBody) {
messager.printError("Unexpected body value", field);
}
if (enumConstantBody != null) {
testEnumConstantBody(enumConstantBody, expectedBinaryName, enclosingClass);
}
System.out.println("\t constant body " + enumConstantBody);
}
/*
* From JLS 8.9.1:
*
* "The optional class body of an enum constant implicitly
* declares an anonymous class (15.9.5) that (i) is a direct
* subclass of the immediately enclosing enum class (8.1.4), and
* (ii) is final (8.1.1.2). The class body is governed by the
* usual rules of anonymous classes; in particular it cannot
* contain any constructors. Instance methods declared in these
* class bodies may be invoked outside the enclosing enum class
* only if they override accessible methods in the enclosing enum
* class (8.4.8)."
*/
private void testEnumConstantBody(TypeElement enumConstBody, String expectedBinaryName, TypeElement enumClass) {
if (enumConstBody.getNestingKind() != NestingKind.ANONYMOUS) {
messager.printError("Class body not an anonymous class", enumConstBody);
}
// Get the TypeElement for the direct superclass.
TypeElement superClass =
(TypeElement)(((DeclaredType)enumConstBody.getSuperclass()).asElement());
if (!superClass.equals(enumClass)) {
messager.printError("Class body is not a direct subclass of the enum", enumConstBody);
}
if (!enumConstBody.getModifiers().contains(Modifier.FINAL)) {
messager.printError("Modifier final missing on class body", enumConstBody);
}
if (!elements.getBinaryName(enumConstBody).contentEquals(expectedBinaryName)) {
messager.printError("Unexpected binary name, expected: " + expectedBinaryName +
", but was: " + elements.getBinaryName(enumConstBody), enumConstBody);
}
return;
}
@interface ExpectedBinaryName {
String value();
}
// Nested classes hosting a variety of different kinds of fields.
private static enum Body {
@ExpectedBinaryName("TestGetEnumConstantBody$Body$1")
GOLGI(true) {
public boolean isOrganelle() {return true;}
},
@ExpectedBinaryName("TestGetEnumConstantBody$Body$2")
HEAVENLY(true) {
public boolean isCelestial() {return true;}
};
private Body(boolean predicate) {
this.predicate = predicate;
}
private boolean predicate;
public static int field = 42;
public void method() {return;}
}
private static enum MetaSyntaxVar {
FOO("foo"),
BAR("bar");
private String lower;
private MetaSyntaxVar(String lower) {
this.lower = lower;
}
int BAZ = 0;
float QUUX = 0.1f;
}
// Instance and static fields.
public static class FieldHolder {
public static final int f1 = 1;
public static final String s = "s";
private Object data;
public FieldHolder(Object data) {
this.data = data;
}
}
}