Java VarHandle类代码示例

import java.lang.invoke.VarHandle; //导入依赖的package包/类
public static <T> boolean tryOnNext(ConditionalSubscriber<T> actual, Object target, VarHandle WIP, VarHandle ERRORS, T item) {
    if ((int)WIP.getAcquire(target) == 0 && WIP.compareAndSet(target, 0, 1)) {
        boolean b = actual.tryOnNext(item);
        if (!WIP.compareAndSet(target, 1, 0)) {
            Throwable ex = ExceptionHelper.terminate(target, ERRORS);
            if (ex == null) {
                actual.onComplete();
            } else {
                actual.onError(ex);
            }
            return false;
        }
        return b;
    }
    return false;
}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
/**
 * Pushes a task. Call only by owner in unshared queues.
 *
 * @param task the task. Caller must ensure non-null.
 * @throws RejectedExecutionException if array cannot be resized
 */
final void push(ForkJoinTask<?> task) {
    int s = top; ForkJoinTask<?>[] a; int al, d;
    if ((a = array) != null && (al = a.length) > 0) {
        int index = (al - 1) & s;
        ForkJoinPool p = pool;
        top = s + 1;
        QA.setRelease(a, index, task);
        if ((d = base - s) == 0 && p != null) {
            VarHandle.fullFence();
            p.signalWork();
        }
        else if (d + al == 1)
            growArray();
    }
}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
/**
 * Initializes or doubles the capacity of array. Call either
 * by owner or with lock held -- it is OK for base, but not
 * top, to move while resizings are in progress.
 */
final ForkJoinTask<?>[] growArray() {
    ForkJoinTask<?>[] oldA = array;
    int oldSize = oldA != null ? oldA.length : 0;
    int size = oldSize > 0 ? oldSize << 1 : INITIAL_QUEUE_CAPACITY;
    if (size < INITIAL_QUEUE_CAPACITY || size > MAXIMUM_QUEUE_CAPACITY)
        throw new RejectedExecutionException("Queue capacity exceeded");
    int oldMask, t, b;
    ForkJoinTask<?>[] a = array = new ForkJoinTask<?>[size];
    if (oldA != null && (oldMask = oldSize - 1) > 0 &&
        (t = top) - (b = base) > 0) {
        int mask = size - 1;
        do { // emulate poll from old array, push to new array
            int index = b & oldMask;
            ForkJoinTask<?> x = (ForkJoinTask<?>)
                QA.getAcquire(oldA, index);
            if (x != null &&
                QA.compareAndSet(oldA, index, x, null))
                a[b & mask] = x;
        } while (++b != t);
        VarHandle.releaseFence();
    }
    return a;
}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
/**
 * Takes next task, if one exists, in LIFO order.  Call only
 * by owner in unshared queues.
 */
final ForkJoinTask<?> pop() {
    int b = base, s = top, al, i; ForkJoinTask<?>[] a;
    if ((a = array) != null && b != s && (al = a.length) > 0) {
        int index = (al - 1) & --s;
        ForkJoinTask<?> t = (ForkJoinTask<?>)
            QA.get(a, index);
        if (t != null &&
            QA.compareAndSet(a, index, t, null)) {
            top = s;
            VarHandle.releaseFence();
            return t;
        }
    }
    return null;
}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
/**
 * If the lock state matches the given stamp, atomically performs one of
 * the following actions. If the stamp represents holding a write
 * lock, returns it.  Or, if a read lock, if the write lock is
 * available, releases the read lock and returns a write stamp.
 * Or, if an optimistic read, returns a write stamp only if
 * immediately available. This method returns zero in all other
 * cases.
 *
 * @param stamp a stamp
 * @return a valid write stamp, or zero on failure
 */
public long tryConvertToWriteLock(long stamp) {
    long a = stamp & ABITS, m, s, next;
    while (((s = state) & SBITS) == (stamp & SBITS)) {
        if ((m = s & ABITS) == 0L) {
            if (a != 0L)
                break;
            if ((next = tryWriteLock(s)) != 0L)
                return next;
        }
        else if (m == WBIT) {
            if (a != m)
                break;
            return stamp;
        }
        else if (m == RUNIT && a != 0L) {
            if (casState(s, next = s - RUNIT + WBIT)) {
                VarHandle.storeStoreFence();
                return next;
            }
        }
        else
            break;
    }
    return 0L;
}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testInstanceFinalFieldUnsupported(VarHandleTestAccessLong recv, VarHandle vh) {
    checkUOE(() -> {
        vh.set(recv, 0xCAFEBABECAFEBABEL);
    });

    checkUOE(() -> {
        vh.setVolatile(recv, 0xCAFEBABECAFEBABEL);
    });

    checkUOE(() -> {
        vh.setRelease(recv, 0xCAFEBABECAFEBABEL);
    });

    checkUOE(() -> {
        vh.setOpaque(recv, 0xCAFEBABECAFEBABEL);
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testStaticFinalFieldUnsupported(VarHandle vh) {
    checkUOE(() -> {
        vh.set(0xCAFEBABECAFEBABEL);
    });

    checkUOE(() -> {
        vh.setVolatile(0xCAFEBABECAFEBABEL);
    });

    checkUOE(() -> {
        vh.setRelease(0xCAFEBABECAFEBABEL);
    });

    checkUOE(() -> {
        vh.setOpaque(0xCAFEBABECAFEBABEL);
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testInstanceFinalFieldUnsupported(VarHandleTestAccessChar recv, VarHandle vh) {
    checkUOE(() -> {
        vh.set(recv, '\u4567');
    });

    checkUOE(() -> {
        vh.setVolatile(recv, '\u4567');
    });

    checkUOE(() -> {
        vh.setRelease(recv, '\u4567');
    });

    checkUOE(() -> {
        vh.setOpaque(recv, '\u4567');
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testStaticFinalFieldUnsupported(VarHandle vh) {
    checkUOE(() -> {
        vh.set('\u4567');
    });

    checkUOE(() -> {
        vh.setVolatile('\u4567');
    });

    checkUOE(() -> {
        vh.setRelease('\u4567');
    });

    checkUOE(() -> {
        vh.setOpaque('\u4567');
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testStaticFinalFieldUnsupported(VarHandle vh) {
    checkUOE(() -> {
        vh.set((short)0x4567);
    });

    checkUOE(() -> {
        vh.setVolatile((short)0x4567);
    });

    checkUOE(() -> {
        vh.setRelease((short)0x4567);
    });

    checkUOE(() -> {
        vh.setOpaque((short)0x4567);
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testStaticFinalFieldUnsupported(VarHandle vh) {
    checkUOE(() -> {
        vh.set(0x89ABCDEF);
    });

    checkUOE(() -> {
        vh.setVolatile(0x89ABCDEF);
    });

    checkUOE(() -> {
        vh.setRelease(0x89ABCDEF);
    });

    checkUOE(() -> {
        vh.setOpaque(0x89ABCDEF);
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testInstanceFinalFieldUnsupported(VarHandleTestAccessByte recv, VarHandle vh) {
    checkUOE(() -> {
        vh.set(recv, (byte)0x23);
    });

    checkUOE(() -> {
        vh.setVolatile(recv, (byte)0x23);
    });

    checkUOE(() -> {
        vh.setRelease(recv, (byte)0x23);
    });

    checkUOE(() -> {
        vh.setOpaque(recv, (byte)0x23);
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
static void testStaticFinalFieldUnsupported(VarHandle vh) {
    checkUOE(() -> {
        vh.set((byte)0x23);
    });

    checkUOE(() -> {
        vh.setVolatile((byte)0x23);
    });

    checkUOE(() -> {
        vh.setRelease((byte)0x23);
    });

    checkUOE(() -> {
        vh.setOpaque((byte)0x23);
    });



}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
public static boolean addThrowable(Object target, VarHandle ERRORS, Throwable t) {
    for (;;) {
        Throwable a = (Throwable) ERRORS.getAcquire(target);
        if (a == TERMINATED) {
            return false;
        }
        Throwable b = CompositeThrowable.combine(a, t);
        if (ERRORS.compareAndSet(target, a, b)) {
            return true;
        }
    }
}
 

import java.lang.invoke.VarHandle; //导入依赖的package包/类
@Test(dataProvider = "typesProvider")
public void testTypes(VarHandle vh, List<java.lang.Class<?>> pts) {
    assertEquals(vh.varType(), short.class);

    assertEquals(vh.coordinateTypes(), pts);

    testTypes(vh);
}