From 3d15c2f1b54c8ce28c2aec82ac2c096c2ffb0f60 Mon Sep 17 00:00:00 2001 From: Roger Riggs Date: Thu, 16 Jun 2022 17:18:09 +0000 Subject: [PATCH] 8287241: Add IdentityException to report that a value object is not valid Reviewed-by: mchung --- .../classes/java/lang/IdentityException.java | 83 +++++++++++++++++++ .../classes/java/lang/ref/Reference.java | 13 +-- .../share/classes/java/util/Objects.java | 60 ++++++++++++++ .../valuetypes/WeakReferenceTest.java | 6 +- 4 files changed, 154 insertions(+), 8 deletions(-) create mode 100644 src/java.base/share/classes/java/lang/IdentityException.java diff --git a/src/java.base/share/classes/java/lang/IdentityException.java b/src/java.base/share/classes/java/lang/IdentityException.java new file mode 100644 index 00000000000..749ec5f5de9 --- /dev/null +++ b/src/java.base/share/classes/java/lang/IdentityException.java @@ -0,0 +1,83 @@ +/* + * Copyright (c) 2022, 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. + */ +package java.lang; + + +/** + * Thrown when an identity object is required but a value object is supplied. + *

+ * Identity objects are required for synchronization and locking. + * Value-based + * objects do not have identity and cannot be used for synchronization or locking. + * + * @since Valhalla + */ +public class IdentityException extends RuntimeException { + @java.io.Serial + private static final long serialVersionUID = 1L; + + /** + * Create an {@code IdentityException} with no message. + */ + public IdentityException() { + } + + /** + * Create an {@code IdentityException} with the class name and default message. + * + * @param clazz the class of the object + */ + public IdentityException(Class clazz) { + super(clazz.getName() + " is not an identity class"); + } + + /** + * Create an {@code IdentityException} with a message. + * + * @param message the detail message; can be {@code null} + */ + public IdentityException(String message) { + super(message); + } + + /** + * Create an {@code IdentityException} with a cause. + * + * @param cause the cause; {@code null} is permitted, and indicates + * that the cause is nonexistent or unknown. + */ + public IdentityException(Throwable cause) { + super(cause); + } + + /** + * Create an {@code IdentityException} with a message and cause. + * + * @param message the detail message; can be {@code null} + * @param cause the cause; {@code null} is permitted, and indicates + * that the cause is nonexistent or unknown. + */ + public IdentityException(String message, Throwable cause) { + super(message, cause); + } +} diff --git a/src/java.base/share/classes/java/lang/ref/Reference.java b/src/java.base/share/classes/java/lang/ref/Reference.java index 3f80e93e107..f2fed0a3d32 100644 --- a/src/java.base/share/classes/java/lang/ref/Reference.java +++ b/src/java.base/share/classes/java/lang/ref/Reference.java @@ -31,11 +31,17 @@ import jdk.internal.access.SharedSecrets; import jdk.internal.ref.Cleaner; +import java.util.Objects; + /** * Abstract base class for reference objects. This class defines the * operations common to all reference objects. Because reference objects are * implemented in close cooperation with the garbage collector, this class may * not be subclassed directly. + *

+ * References can only refer to identity objects. + * Attempts to create a reference to a {@linkplain Class#isValue() value object} + * results in an {@link IdentityException}. * * @author Mark Reinhold * @since 1.2 @@ -498,11 +504,8 @@ protected Object clone() throws CloneNotSupportedException { } Reference(T referent, ReferenceQueue queue) { - if (referent != null && referent.getClass().isValue()) { - Class c = referent.getClass(); - throw new IllegalArgumentException("cannot reference a " + - (c.isPrimitiveClass() ? "primitive class " : "value class ") + - c.getName()); + if (referent != null) { + Objects.requireIdentity(referent); } this.referent = referent; this.queue = (queue == null) ? ReferenceQueue.NULL : queue; diff --git a/src/java.base/share/classes/java/util/Objects.java b/src/java.base/share/classes/java/util/Objects.java index 90b6393c72e..e40085a3cc7 100644 --- a/src/java.base/share/classes/java/util/Objects.java +++ b/src/java.base/share/classes/java/util/Objects.java @@ -189,6 +189,66 @@ public static String toIdentityString(Object o) { return o.getClass().getName() + "@" + Integer.toHexString(System.identityHashCode(o)); } + /** + * Checks that the specified object reference is an identity object. + * + * @param obj the object reference to check for identity + * @param the type of the reference + * @return {@code obj} if {@code obj} is an identity object + * @throws NullPointerException if {@code obj} is {@code null} + * @throws IdentityException if {@code obj} is not an identity object + * @since Valhalla + */ + @ForceInline + public static T requireIdentity(T obj) { + Objects.requireNonNull(obj); + var cl = obj.getClass(); + if (cl.isValue()) + throw new IdentityException(cl); + return obj; + } + + /** + * Checks that the specified object reference is an identity object. + * + * @param obj the object reference to check for identity + * @param message detail message to be used in the event that an + * {@code IdentityException} is thrown; may be null + * @param the type of the reference + * @return {@code obj} if {@code obj} is an identity object + * @throws NullPointerException if {@code obj} is {@code null} + * @throws IdentityException if {@code obj} is not an identity object + * @since Valhalla + */ + @ForceInline + public static T requireIdentity(T obj, String message) { + Objects.requireNonNull(obj); + if (obj.getClass().isValue()) + throw new IdentityException(message); + return obj; + } + + /** + * Checks that the specified object reference is an identity object. + * + * @param obj the object reference to check for identity + * @param messageSupplier supplier of the detail message to be + * used in the event that an {@code IdentityException} is thrown; may be null + * @param the type of the reference + * @return {@code obj} if {@code obj} is an identity object + * @throws NullPointerException if {@code obj} is {@code null} + * @throws IdentityException if {@code obj} is not an identity object + * @since Valhalla + */ + @ForceInline + public static T requireIdentity(T obj, Supplier messageSupplier) { + Objects.requireNonNull(obj); + if (obj.getClass().isValue()) + throw new IdentityException(messageSupplier == null ? + null : messageSupplier.get()); + return obj; + } + /** * Returns 0 if the arguments are identical and {@code * c.compare(a, b)} otherwise. diff --git a/test/jdk/valhalla/valuetypes/WeakReferenceTest.java b/test/jdk/valhalla/valuetypes/WeakReferenceTest.java index 837822768d8..520b5b0ef72 100644 --- a/test/jdk/valhalla/valuetypes/WeakReferenceTest.java +++ b/test/jdk/valhalla/valuetypes/WeakReferenceTest.java @@ -1,5 +1,5 @@ /* - * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2019, 2022, 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 @@ -37,13 +37,13 @@ @Test public class WeakReferenceTest { - @Test(expectedExceptions = IllegalArgumentException.class) + @Test(expectedExceptions = IdentityException.class) static void test1() { Point.ref p = new Point(10,20); WeakReference r = new WeakReference<>(p); } - @Test(expectedExceptions = IllegalArgumentException.class) + @Test(expectedExceptions = IdentityException.class) static void test2() { ReferenceQueue q = new ReferenceQueue<>(); Point.ref p = new Point(1,2);