diff -r 836adbf7a2cd -r 3317bb8137f4 jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicLongFieldUpdater.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/jdk/src/java.base/share/classes/java/util/concurrent/atomic/AtomicLongFieldUpdater.java Sun Aug 17 15:54:13 2014 +0100 @@ -0,0 +1,608 @@ +/* + * 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. + */ + +/* + * This file is available under and governed by the GNU General Public + * License version 2 only, as published by the Free Software Foundation. + * However, the following notice accompanied the original version of this + * file: + * + * Written by Doug Lea with assistance from members of JCP JSR-166 + * Expert Group and released to the public domain, as explained at + * http://creativecommons.org/publicdomain/zero/1.0/ + */ + +package java.util.concurrent.atomic; +import java.util.function.LongUnaryOperator; +import java.util.function.LongBinaryOperator; +import sun.misc.Unsafe; +import java.lang.reflect.Field; +import java.lang.reflect.Modifier; +import java.security.AccessController; +import java.security.PrivilegedExceptionAction; +import java.security.PrivilegedActionException; +import sun.reflect.CallerSensitive; +import sun.reflect.Reflection; + +/** + * A reflection-based utility that enables atomic updates to + * designated {@code volatile long} fields of designated classes. + * This class is designed for use in atomic data structures in which + * several fields of the same node are independently subject to atomic + * updates. + * + *
Note that the guarantees of the {@code compareAndSet}
+ * method in this class are weaker than in other atomic classes.
+ * Because this class cannot ensure that all uses of the field
+ * are appropriate for purposes of atomic access, it can
+ * guarantee atomicity only with respect to other invocations of
+ * {@code compareAndSet} and {@code set} on the same updater.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ * @param May fail
+ * spuriously and does not provide ordering guarantees, so is
+ * only rarely an appropriate alternative to {@code compareAndSet}.
+ *
+ * @param obj An object whose field to conditionally set
+ * @param expect the expected value
+ * @param update the new value
+ * @return {@code true} if successful
+ * @throws ClassCastException if {@code obj} is not an instance
+ * of the class possessing the field established in the constructor
+ */
+ public abstract boolean weakCompareAndSet(T obj, long expect, long update);
+
+ /**
+ * Sets the field of the given object managed by this updater to the
+ * given updated value. This operation is guaranteed to act as a volatile
+ * store with respect to subsequent invocations of {@code compareAndSet}.
+ *
+ * @param obj An object whose field to set
+ * @param newValue the new value
+ */
+ public abstract void set(T obj, long newValue);
+
+ /**
+ * Eventually sets the field of the given object managed by this
+ * updater to the given updated value.
+ *
+ * @param obj An object whose field to set
+ * @param newValue the new value
+ * @since 1.6
+ */
+ public abstract void lazySet(T obj, long newValue);
+
+ /**
+ * Gets the current value held in the field of the given object managed
+ * by this updater.
+ *
+ * @param obj An object whose field to get
+ * @return the current value
+ */
+ public abstract long get(T obj);
+
+ /**
+ * Atomically sets the field of the given object managed by this updater
+ * to the given value and returns the old value.
+ *
+ * @param obj An object whose field to get and set
+ * @param newValue the new value
+ * @return the previous value
+ */
+ public long getAndSet(T obj, long newValue) {
+ long prev;
+ do {
+ prev = get(obj);
+ } while (!compareAndSet(obj, prev, newValue));
+ return prev;
+ }
+
+ /**
+ * Atomically increments by one the current value of the field of the
+ * given object managed by this updater.
+ *
+ * @param obj An object whose field to get and set
+ * @return the previous value
+ */
+ public long getAndIncrement(T obj) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = prev + 1;
+ } while (!compareAndSet(obj, prev, next));
+ return prev;
+ }
+
+ /**
+ * Atomically decrements by one the current value of the field of the
+ * given object managed by this updater.
+ *
+ * @param obj An object whose field to get and set
+ * @return the previous value
+ */
+ public long getAndDecrement(T obj) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = prev - 1;
+ } while (!compareAndSet(obj, prev, next));
+ return prev;
+ }
+
+ /**
+ * Atomically adds the given value to the current value of the field of
+ * the given object managed by this updater.
+ *
+ * @param obj An object whose field to get and set
+ * @param delta the value to add
+ * @return the previous value
+ */
+ public long getAndAdd(T obj, long delta) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = prev + delta;
+ } while (!compareAndSet(obj, prev, next));
+ return prev;
+ }
+
+ /**
+ * Atomically increments by one the current value of the field of the
+ * given object managed by this updater.
+ *
+ * @param obj An object whose field to get and set
+ * @return the updated value
+ */
+ public long incrementAndGet(T obj) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = prev + 1;
+ } while (!compareAndSet(obj, prev, next));
+ return next;
+ }
+
+ /**
+ * Atomically decrements by one the current value of the field of the
+ * given object managed by this updater.
+ *
+ * @param obj An object whose field to get and set
+ * @return the updated value
+ */
+ public long decrementAndGet(T obj) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = prev - 1;
+ } while (!compareAndSet(obj, prev, next));
+ return next;
+ }
+
+ /**
+ * Atomically adds the given value to the current value of the field of
+ * the given object managed by this updater.
+ *
+ * @param obj An object whose field to get and set
+ * @param delta the value to add
+ * @return the updated value
+ */
+ public long addAndGet(T obj, long delta) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = prev + delta;
+ } while (!compareAndSet(obj, prev, next));
+ return next;
+ }
+
+ /**
+ * Atomically updates the field of the given object managed by this updater
+ * with the results of applying the given function, returning the previous
+ * value. The function should be side-effect-free, since it may be
+ * re-applied when attempted updates fail due to contention among threads.
+ *
+ * @param obj An object whose field to get and set
+ * @param updateFunction a side-effect-free function
+ * @return the previous value
+ * @since 1.8
+ */
+ public final long getAndUpdate(T obj, LongUnaryOperator updateFunction) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = updateFunction.applyAsLong(prev);
+ } while (!compareAndSet(obj, prev, next));
+ return prev;
+ }
+
+ /**
+ * Atomically updates the field of the given object managed by this updater
+ * with the results of applying the given function, returning the updated
+ * value. The function should be side-effect-free, since it may be
+ * re-applied when attempted updates fail due to contention among threads.
+ *
+ * @param obj An object whose field to get and set
+ * @param updateFunction a side-effect-free function
+ * @return the updated value
+ * @since 1.8
+ */
+ public final long updateAndGet(T obj, LongUnaryOperator updateFunction) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = updateFunction.applyAsLong(prev);
+ } while (!compareAndSet(obj, prev, next));
+ return next;
+ }
+
+ /**
+ * Atomically updates the field of the given object managed by this
+ * updater with the results of applying the given function to the
+ * current and given values, returning the previous value. The
+ * function should be side-effect-free, since it may be re-applied
+ * when attempted updates fail due to contention among threads. The
+ * function is applied with the current value as its first argument,
+ * and the given update as the second argument.
+ *
+ * @param obj An object whose field to get and set
+ * @param x the update value
+ * @param accumulatorFunction a side-effect-free function of two arguments
+ * @return the previous value
+ * @since 1.8
+ */
+ public final long getAndAccumulate(T obj, long x,
+ LongBinaryOperator accumulatorFunction) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = accumulatorFunction.applyAsLong(prev, x);
+ } while (!compareAndSet(obj, prev, next));
+ return prev;
+ }
+
+ /**
+ * Atomically updates the field of the given object managed by this
+ * updater with the results of applying the given function to the
+ * current and given values, returning the updated value. The
+ * function should be side-effect-free, since it may be re-applied
+ * when attempted updates fail due to contention among threads. The
+ * function is applied with the current value as its first argument,
+ * and the given update as the second argument.
+ *
+ * @param obj An object whose field to get and set
+ * @param x the update value
+ * @param accumulatorFunction a side-effect-free function of two arguments
+ * @return the updated value
+ * @since 1.8
+ */
+ public final long accumulateAndGet(T obj, long x,
+ LongBinaryOperator accumulatorFunction) {
+ long prev, next;
+ do {
+ prev = get(obj);
+ next = accumulatorFunction.applyAsLong(prev, x);
+ } while (!compareAndSet(obj, prev, next));
+ return next;
+ }
+
+ private static class CASUpdater