| /* |
| * Copyright (c) 2015, 2015, 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 org.graalvm.compiler.word; |
| |
| import java.util.concurrent.atomic.AtomicLong; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| /** |
| * A {@link WordBase word} value that may be updated atomically. See the |
| * {@link java.util.concurrent.atomic} package specification for description of the properties of |
| * atomic variables. |
| * |
| * Similar to {@link AtomicReference}, but for {@link WordBase word} types. A dedicated |
| * implementation is necessary because Object and word types cannot be mixed. |
| */ |
| public class AtomicWord<T extends WordBase> { |
| |
| /** |
| * For simplicity, we convert the word value to a long and delegate to existing atomic |
| * operations. |
| */ |
| protected final AtomicLong value; |
| |
| /** |
| * Creates a new AtomicLong with initial value {@link Word#zero}. |
| */ |
| public AtomicWord() { |
| value = new AtomicLong(); |
| } |
| |
| /** |
| * Gets the current value. |
| * |
| * @return the current value |
| */ |
| @SuppressWarnings("unchecked") |
| public final T get() { |
| return (T) Word.unsigned(value.get()); |
| } |
| |
| /** |
| * Sets to the given value. |
| * |
| * @param newValue the new value |
| */ |
| public final void set(T newValue) { |
| value.set(newValue.rawValue()); |
| } |
| |
| /** |
| * Atomically sets to the given value and returns the old value. |
| * |
| * @param newValue the new value |
| * @return the previous value |
| */ |
| @SuppressWarnings("unchecked") |
| public final T getAndSet(T newValue) { |
| return (T) Word.unsigned(value.getAndSet(newValue.rawValue())); |
| } |
| |
| /** |
| * Atomically sets the value to the given updated value if the current value {@code ==} the |
| * expected value. |
| * |
| * @param expect the expected value |
| * @param update the new value |
| * @return {@code true} if successful. False return indicates that the actual value was not |
| * equal to the expected value. |
| */ |
| public final boolean compareAndSet(T expect, T update) { |
| return value.compareAndSet(expect.rawValue(), update.rawValue()); |
| } |
| } |