java.lang.invoke.VarHandle#storeStoreFence ( )源码实例Demo

/**
 * 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;
}
 

@Override
public void start(long gen, String taskName, String tagName, long tagId, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, taskName);
  STRINGS.setOpaque(tagNames, i, tagName);
  LONGS.setOpaque(tagIds, i, tagId);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + START_T_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void start(long gen, String taskName, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, taskName);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + START_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void start(long gen, String taskName, String subTaskName, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, taskName);
  STRINGS.setOpaque(tagNames, i, subTaskName);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + START_S_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void link(long gen, long linkId) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  LONGS.setOpaque(tagIds, i, linkId);
  LONGS.setOpaque(genOps, i, gen + LINK_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void stop(long gen, String taskName, String tagName, long tagId, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, taskName);
  STRINGS.setOpaque(tagNames, i, tagName);
  LONGS.setOpaque(tagIds, i, tagId);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + STOP_T_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void stop(long gen, String taskName, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, taskName);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + STOP_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void stop(long gen, String taskName, String subTaskName, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, taskName);
  STRINGS.setOpaque(tagNames, i, subTaskName);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + STOP_S_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void event(long gen, String eventName, String tagName, long tagId, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, eventName);
  STRINGS.setOpaque(tagNames, i, tagName);
  LONGS.setOpaque(tagIds, i, tagId);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + EVENT_T_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void event(long gen, String eventName, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, eventName);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + EVENT_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void event(long gen, String eventName, String subEventName, long nanoTime) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(taskNames, i, eventName);
  STRINGS.setOpaque(tagNames, i, subEventName);
  LONGS.setOpaque(nanoTimes, i, nanoTime);
  LONGS.setOpaque(genOps, i, gen + EVENT_S_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void attachTag(long gen, String tagName, long tagId) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(tagNames, i, tagName);
  LONGS.setOpaque(tagIds, i, tagId);
  LONGS.setOpaque(genOps, i, gen + ATTACH_T_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void attachKeyedTag(long gen, String name, long value) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(tagNames, i, name);
  LONGS.setOpaque(tagIds, i, value);
  LONGS.setOpaque(genOps, i, gen + ATTACH_SN_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void attachKeyedTag(long gen, String name, long value0, long value1) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(tagNames, i, name);
  LONGS.setOpaque(tagIds, i, value0);
  LONGS.setOpaque(nanoTimes, i, value1);
  LONGS.setOpaque(genOps, i, gen + ATTACH_SNN_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void attachKeyedTag(long gen, String name, String value) {
  long localIdx = (long) IDX.get(this);
  int i = (int) (localIdx & maxEventsMax);
  STRINGS.setOpaque(tagNames, i, name);
  STRINGS.setOpaque(taskNames, i, value);
  LONGS.setOpaque(genOps, i, gen + ATTACH_SS_OP);
  IDX.setRelease(this, localIdx + 1);
  VarHandle.storeStoreFence();
}
 

@Override
public void resetForTest() {
  Arrays.fill(taskNames, null);
  Arrays.fill(markers, null);
  Arrays.fill(tagNames, null);
  Arrays.fill(tagIds, 0);
  Arrays.fill(nanoTimes, 0);
  Arrays.fill(genOps, 0);
  IDX.setRelease(this, 0L);
  VarHandle.storeStoreFence();
}
 

private long tryWriteLock(long s) {
    // assert (s & ABITS) == 0L;
    long next;
    if (casState(s, next = s | WBIT)) {
        VarHandle.storeStoreFence();
        return next;
    }
    return 0L;
}
 

public static String doIt() throws NoSuchFieldException, IllegalAccessException {
	VarHandle.storeStoreFence();

       MethodHandles.Lookup l = MethodHandles.lookup();
       VarHandle  VALUE = l.findVarHandle(VarHandlerTest.class, "value", int.class);
	
       VarHandlerTest vht = new VarHandlerTest();
       
       int somting = (int) VALUE.getAndSet(vht, 16);
       
	return "ok: " + somting;
}