/** constructor initializes to given reference and stamp */
public void testConstructor() {
AtomicStampedReference ai = new AtomicStampedReference(one, 0);
assertSame(one, ai.getReference());
assertEquals(0, ai.getStamp());
AtomicStampedReference a2 = new AtomicStampedReference(null, 1);
assertNull(a2.getReference());
assertEquals(1, a2.getStamp());
}
/**
* @param updateSeq Update sequence.
* @return {@code True} if entry has been transitioned to state EVICTED.
*/
boolean tryEvict(boolean updateSeq) {
if (state.getReference() != RENTING || state.getStamp() != 0 || groupReserved()) return false;
// Attempt to evict partition entries from cache.
clearAll();
if (map.isEmpty() && state.compareAndSet(RENTING, EVICTED, 0, 0)) {
if (log.isDebugEnabled()) log.debug("Evicted partition: " + this);
if (!GridQueryProcessor.isEnabled(cctx.config())) clearSwap();
if (cctx.isDrEnabled()) cctx.dr().partitionEvicted(id);
cctx.dataStructures().onPartitionEvicted(id);
rent.onDone();
((GridDhtPreloader) cctx.preloader()).onPartitionEvicted(this, updateSeq);
clearDeferredDeletes();
return true;
}
return false;
}
/**
* Adds group reservation to this partition.
*
* @param r Reservation.
* @return {@code false} If such reservation already added.
*/
public boolean addReservation(GridDhtPartitionsReservation r) {
assert state.getReference() != EVICTED : "we can reserve only active partitions";
assert state.getStamp() != 0
: "partition must be already reserved before adding group reservation";
return reservations.addIfAbsent(r);
}
/** get returns the last values of reference and stamp set */
public void testGetSet() {
int[] mark = new int[1];
AtomicStampedReference ai = new AtomicStampedReference(one, 0);
assertSame(one, ai.getReference());
assertEquals(0, ai.getStamp());
assertSame(one, ai.get(mark));
assertEquals(0, mark[0]);
ai.set(two, 0);
assertSame(two, ai.getReference());
assertEquals(0, ai.getStamp());
assertSame(two, ai.get(mark));
assertEquals(0, mark[0]);
ai.set(one, 1);
assertSame(one, ai.getReference());
assertEquals(1, ai.getStamp());
assertSame(one, ai.get(mark));
assertEquals(1, mark[0]);
}
/**
* Reserves a partition so it won't be cleared.
*
* @return {@code True} if reserved.
*/
@Override
public boolean reserve() {
while (true) {
int reservations = state.getStamp();
GridDhtPartitionState s = state.getReference();
if (s == EVICTED) return false;
if (state.compareAndSet(s, s, reservations, reservations + 1)) return true;
}
}
/** compareAndSet in one thread enables another waiting for reference value to succeed */
public void testCompareAndSetInMultipleThreads() throws Exception {
final AtomicStampedReference ai = new AtomicStampedReference(one, 0);
Thread t =
new Thread(
new CheckedRunnable() {
public void realRun() {
while (!ai.compareAndSet(two, three, 0, 0)) Thread.yield();
}
});
t.start();
assertTrue(ai.compareAndSet(one, two, 0, 0));
t.join(LONG_DELAY_MS);
assertFalse(t.isAlive());
assertSame(three, ai.getReference());
assertEquals(0, ai.getStamp());
}
/** Releases previously reserved partition. */
@Override
public void release() {
while (true) {
int reservations = state.getStamp();
if (reservations == 0) return;
GridDhtPartitionState s = state.getReference();
assert s != EVICTED;
// Decrement reservations.
if (state.compareAndSet(s, s, reservations, --reservations)) {
tryEvict(true);
break;
}
}
}
/**
* @param updateSeq Update sequence.
* @return Future to signal that this node is no longer an owner or backup.
*/
IgniteInternalFuture<?> rent(boolean updateSeq) {
while (true) {
int reservations = state.getStamp();
GridDhtPartitionState s = state.getReference();
if (s == RENTING || s == EVICTED) return rent;
if (state.compareAndSet(s, RENTING, reservations, reservations)) {
if (log.isDebugEnabled()) log.debug("Moved partition to RENTING state: " + this);
// Evict asynchronously, as the 'rent' method may be called
// from within write locks on local partition.
tryEvictAsync(updateSeq);
break;
}
}
return rent;
}
/** @return {@code True} if transitioned to OWNING state. */
boolean own() {
while (true) {
int reservations = state.getStamp();
GridDhtPartitionState s = state.getReference();
if (s == RENTING || s == EVICTED) return false;
if (s == OWNING) return true;
assert s == MOVING;
if (state.compareAndSet(MOVING, OWNING, reservations, reservations)) {
if (log.isDebugEnabled()) log.debug("Owned partition: " + this);
// No need to keep history any more.
evictHist = null;
return true;
}
}
}
public boolean attemptModifyASR() {
boolean modified = false;
IntendedModification currentlyOngoingMod = ongoingMod.getReference();
int stamp = ongoingMod.getStamp();
if (currentlyOngoingMod == null) {
// copy data structure state - for use
// in intended modification
// prepare intended modification
IntendedModification newMod = new IntendedModification();
// compareAndSet(V expectedReference, V newReference, int expectedStamp, int newStamp) {}
boolean modSubmitted = ongoingMod.compareAndSet(null, newMod, stamp, stamp + 1);
if (modSubmitted) {
// complete modification via a series of compare-and-swap operations.
// note: other threads may assist in completing the compare-and-swap
// operations, so some CAS may fail
modified = true;
}
} else {
// attempt to complete ongoing modification, so the data structure is fired up
// to allow access from this thread.
modified = false;
}
return modified;
}
/** @return Partition state. */
public GridDhtPartitionState state() {
return state.getReference();
}
public State getState() {
return state.getReference();
}