8308040: Evaluate new public types in non-public classes

Reviewed-by: rriggs, darcy

src/java.base/share/classes/java/lang/runtime/ReferenceKey.java

@@ -25,7 +25,6 @@
 
 package java.lang.runtime;
 
-import java.lang.ref.Reference;
 import java.lang.ref.ReferenceQueue;
 import java.lang.ref.SoftReference;
 import java.lang.ref.WeakReference;
@@ -44,7 +43,7 @@ import java.util.Objects;
  * Warning: This class is part of PreviewFeature.Feature.STRING_TEMPLATES.
  *          Do not rely on its availability.
  */
-interface ReferenceKey<T> {
+sealed interface ReferenceKey<T> permits StrongReferenceKey, WeakReferenceKey, SoftReferenceKey {
     /**
      * {@return the value of the unwrapped key}
      */
@@ -55,176 +54,4 @@ interface ReferenceKey<T> {
      */
     void unused();
 
-    /**
-     * {@link WeakReference} wrapper key for entries in the backing map.
-     *
-     * @param <T> key type
-     *
-     * @since 21
-     */
-    class WeakKey<T> extends WeakReference<T> implements ReferenceKey<T> {
-        /**
-         * Saved hashcode of the key. Used when {@link WeakReference} is
-         * null.
-         */
-        private final int hashcode;
-
-        /**
-         * Private constructor.
-         *
-         * @param key   unwrapped key value
-         * @param queue reference queue
-         */
-        WeakKey(T key, ReferenceQueue<T> queue) {
-            super(key, queue);
-            this.hashcode = Objects.hashCode(key);
-        }
-
-        /**
-         * Cleanup unused key. No need to enqueue since the key did not make it
-         * into the map.
-         */
-        @Override
-        public void unused() {
-            clear();
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            // Necessary when removing a null reference
-            if (obj == this) {
-                return true;
-            }
-            // Necessary when comparing an unwrapped key
-            if (obj instanceof ReferenceKey<?> key) {
-                obj = key.get();
-            }
-            return Objects.equals(get(), obj);
-        }
-
-        @Override
-        public int hashCode() {
-            // Use saved hashcode
-            return hashcode;
-        }
-
-        @Override
-        public String toString() {
-            return this.getClass().getCanonicalName() + "#" + System.identityHashCode(this);
-        }
-    }
-
-    /**
-     * {@link SoftReference} wrapper key for entries in the backing map.
-     *
-     * @param <T> key type
-     *
-     * @since 21
-     */
-    class SoftKey<T> extends SoftReference<T> implements ReferenceKey<T> {
-        /**
-         * Saved hashcode of the key. Used when {@link SoftReference} is
-         * null.
-         */
-        private final int hashcode;
-
-        /**
-         * Private constructor.
-         *
-         * @param key   unwrapped key value
-         * @param queue reference queue
-         */
-        SoftKey(T key, ReferenceQueue<T> queue) {
-            super(key, queue);
-            this.hashcode = Objects.hashCode(key);
-        }
-
-        /**
-         * Cleanup unused key. No need to enqueue since the key did not make it
-         * into the map.
-         */
-        @Override
-        public void unused() {
-            clear();
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            // Necessary when removing a null reference
-            if (obj == this) {
-                return true;
-            }
-            // Necessary when comparing an unwrapped key
-            if (obj instanceof ReferenceKey<?> key) {
-                obj = key.get();
-            }
-            return Objects.equals(get(), obj);
-        }
-
-        @Override
-        public int hashCode() {
-            // Use saved hashcode
-            return hashcode;
-        }
-
-        @Override
-        public String toString() {
-            return this.getClass().getCanonicalName() + "#" + System.identityHashCode(this);
-        }
-    }
-
-    /**
-     * Wrapper for querying the backing map. Avoids the overhead of an
-     * {@link Reference} object.
-     *
-     * @param <T> key type
-     *
-     * @since 21
-     */
-    class StrongKey<T> implements ReferenceKey<T> {
-        T key;
-
-        /**
-         * Private constructor.
-         *
-         * @param key unwrapped key value
-         */
-        StrongKey(T key) {
-            this.key = key;
-        }
-
-        /**
-         * {@return the unwrapped key}
-         */
-        @Override
-        public T get() {
-            return key;
-        }
-
-        @Override
-        public void unused() {
-            key = null;
-        }
-
-        @Override
-        public boolean equals(Object obj) {
-            // Necessary when comparing an unwrapped key
-            if (obj instanceof ReferenceKey<?> key) {
-                obj = key.get();
-            }
-            return Objects.equals(get(), obj);
-        }
-
-        @Override
-        public int hashCode() {
-            // Use unwrapped key hash code
-            return get().hashCode();
-        }
-
-        @Override
-        public String toString() {
-            return this.getClass().getCanonicalName() + "#" + System.identityHashCode(this);
-        }
-    }
-
 }

src/java.base/share/classes/java/lang/runtime/ReferencedKeyMap.java

@@ -95,7 +95,7 @@ final class ReferencedKeyMap<K, V> implements Map<K, V> {
     private final Map<ReferenceKey<K>, V> map;
 
     /**
-     * {@link ReferenceQueue} for cleaning up {@link ReferenceKey.WeakKey EntryKeys}.
+     * {@link ReferenceQueue} for cleaning up {@link WeakReferenceKey EntryKeys}.
      */
     private final ReferenceQueue<K> stale;
 
@@ -153,9 +153,9 @@ final class ReferencedKeyMap<K, V> implements Map<K, V> {
     @SuppressWarnings("unchecked")
     private ReferenceKey<K> entryKey(Object key) {
         if (isSoft) {
-            return new ReferenceKey.SoftKey<>((K)key, stale);
+            return new SoftReferenceKey<>((K)key, stale);
         } else {
-            return new ReferenceKey.WeakKey<>((K)key, stale);
+            return new WeakReferenceKey<>((K)key, stale);
         }
     }
 
@@ -166,7 +166,7 @@ final class ReferencedKeyMap<K, V> implements Map<K, V> {
      */
     @SuppressWarnings("unchecked")
     private ReferenceKey<K> lookupKey(Object key) {
-        return new ReferenceKey.StrongKey<>((K)key);
+        return new StrongReferenceKey<>((K)key);
     }
 
     @Override
@@ -323,7 +323,7 @@ final class ReferencedKeyMap<K, V> implements Map<K, V> {
     @SuppressWarnings("unchecked")
     public void removeStaleReferences() {
         while (true) {
-            ReferenceKey.WeakKey<K> key = (ReferenceKey.WeakKey<K>)stale.poll();
+            WeakReferenceKey<K> key = (WeakReferenceKey<K>)stale.poll();
             if (key == null) {
                 break;
             }

src/java.base/share/classes/java/lang/runtime/SoftReferenceKey.java

@@ -0,0 +1,92 @@
+/*
+ * 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.runtime;
+
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.SoftReference;
+import java.util.Objects;
+
+/**
+ * {@link SoftReference} wrapper key for entries in the backing map.
+ *
+ * @param <T> key type
+ *
+ * @since 21
+ *
+ * Warning: This class is part of PreviewFeature.Feature.STRING_TEMPLATES.
+ *          Do not rely on its availability.
+ */
+final class SoftReferenceKey<T> extends SoftReference<T> implements ReferenceKey<T> {
+    /**
+     * Saved hashcode of the key. Used when {@link SoftReference} is
+     * null.
+     */
+    private final int hashcode;
+
+    /**
+     * Package-Protected constructor.
+     *
+     * @param key   unwrapped key value
+     * @param queue reference queue
+     */
+    SoftReferenceKey(T key, ReferenceQueue<T> queue) {
+        super(key, queue);
+        this.hashcode = Objects.hashCode(key);
+    }
+
+    /**
+     * Cleanup unused key. No need to enqueue since the key did not make it
+     * into the map.
+     */
+    @Override
+    public void unused() {
+        clear();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        // Necessary when removing a null reference
+        if (obj == this) {
+            return true;
+        }
+        // Necessary when comparing an unwrapped key
+        if (obj instanceof ReferenceKey<?> key) {
+            obj = key.get();
+        }
+        return Objects.equals(get(), obj);
+    }
+
+    @Override
+    public int hashCode() {
+        // Use saved hashcode
+        return hashcode;
+    }
+
+    @Override
+    public String toString() {
+        return this.getClass().getCanonicalName() + "#" + System.identityHashCode(this);
+    }
+}

src/java.base/share/classes/java/lang/runtime/StrongReferenceKey.java

@@ -0,0 +1,85 @@
+/*
+ * 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.runtime;
+
+import java.util.Objects;
+
+/**
+ * Wrapper for querying the backing map. Avoids the overhead of an
+ * {@link java.lang.ref.Reference} object.
+ *
+ * @param <T> key type
+ *
+ * @since 21
+ *
+ * Warning: This class is part of PreviewFeature.Feature.STRING_TEMPLATES.
+ *          Do not rely on its availability.
+ */
+final class StrongReferenceKey<T> implements ReferenceKey<T> {
+    T key;
+
+    /**
+     * Package-Protected constructor.
+     *
+     * @param key unwrapped key value
+     */
+    StrongReferenceKey(T key) {
+        this.key = key;
+    }
+
+    /**
+     * {@return the unwrapped key}
+     */
+    @Override
+    public T get() {
+        return key;
+    }
+
+    @Override
+    public void unused() {
+        key = null;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        // Necessary when comparing an unwrapped key
+        if (obj instanceof ReferenceKey<?> key) {
+            obj = key.get();
+        }
+        return Objects.equals(get(), obj);
+    }
+
+    @Override
+    public int hashCode() {
+        // Use unwrapped key hash code
+        return get().hashCode();
+    }
+
+    @Override
+    public String toString() {
+        return this.getClass().getCanonicalName() + "#" + System.identityHashCode(this);
+    }
+}

src/java.base/share/classes/java/lang/runtime/WeakReferenceKey.java

@@ -0,0 +1,92 @@
+/*
+ * 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * 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.runtime;
+
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+import java.util.Objects;
+
+/**
+ * {@link WeakReference} wrapper key for entries in the backing map.
+ *
+ * @param <T> key type
+ *
+ * @since 21
+ *
+ * Warning: This class is part of PreviewFeature.Feature.STRING_TEMPLATES.
+ *          Do not rely on its availability.
+ */
+final class WeakReferenceKey<T> extends WeakReference<T> implements ReferenceKey<T> {
+    /**
+     * Saved hashcode of the key. Used when {@link WeakReference} is
+     * null.
+     */
+    private final int hashcode;
+
+    /**
+     * Package-Protected constructor.
+     *
+     * @param key   unwrapped key value
+     * @param queue reference queue
+     */
+    WeakReferenceKey(T key, ReferenceQueue<T> queue) {
+        super(key, queue);
+        this.hashcode = Objects.hashCode(key);
+    }
+
+    /**
+     * Cleanup unused key. No need to enqueue since the key did not make it
+     * into the map.
+     */
+    @Override
+    public void unused() {
+        clear();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        // Necessary when removing a null reference
+        if (obj == this) {
+            return true;
+        }
+        // Necessary when comparing an unwrapped key
+        if (obj instanceof ReferenceKey<?> key) {
+            obj = key.get();
+        }
+        return Objects.equals(get(), obj);
+    }
+
+    @Override
+    public int hashCode() {
+        // Use saved hashcode
+        return hashcode;
+    }
+
+    @Override
+    public String toString() {
+        return this.getClass().getCanonicalName() + "#" + System.identityHashCode(this);
+    }
+}