/**
     * Waits until total number of events processed is equal or greater then argument passed.
     *
     * @param cnt Number of events to wait.
     * @param timeout Timeout to wait.
     * @return {@code True} if successfully waited, {@code false} if timeout happened.
     * @throws InterruptedException If thread is interrupted.
     */
    public synchronized boolean awaitEvents(int cnt, long timeout) throws InterruptedException {
      long start = U.currentTimeMillis();

      long now = start;

      while (start + timeout > now) {
        if (evtCnt >= cnt) return true;

        wait(start + timeout - now);

        now = U.currentTimeMillis();
      }

      return false;
    }
  /** {@inheritDoc} */
  @Override
  protected final boolean tryReleaseShared(int ignore) {
    endTime = U.currentTimeMillis();

    // Always signal after setting final done status.
    return true;
  }
/** Key partition. */
public class GridDhtLocalPartition implements Comparable<GridDhtLocalPartition>, GridReservable {
  /** Maximum size for delete queue. */
  public static final int MAX_DELETE_QUEUE_SIZE =
      Integer.getInteger(IGNITE_ATOMIC_CACHE_DELETE_HISTORY_SIZE, 200_000);

  /** Static logger to avoid re-creation. */
  private static final AtomicReference<IgniteLogger> logRef = new AtomicReference<>();

  /** Logger. */
  private static volatile IgniteLogger log;

  /** Partition ID. */
  private final int id;

  /** State. */
  @GridToStringExclude
  private final AtomicStampedReference<GridDhtPartitionState> state =
      new AtomicStampedReference<>(MOVING, 0);

  /** Rent future. */
  @GridToStringExclude private final GridFutureAdapter<?> rent;

  /** Entries map. */
  private final ConcurrentMap<KeyCacheObject, GridDhtCacheEntry> map;

  /** Context. */
  private final GridCacheContext cctx;

  /** Create time. */
  @GridToStringExclude private final long createTime = U.currentTimeMillis();

  /** Eviction history. */
  private volatile Map<KeyCacheObject, GridCacheVersion> evictHist = new HashMap<>();

  /** Lock. */
  private final ReentrantLock lock = new ReentrantLock();

  /** Public size counter. */
  private final LongAdder8 mapPubSize = new LongAdder8();

  /** Remove queue. */
  private final GridCircularBuffer<T2<KeyCacheObject, GridCacheVersion>> rmvQueue;

  /** Group reservations. */
  private final CopyOnWriteArrayList<GridDhtPartitionsReservation> reservations =
      new CopyOnWriteArrayList<>();

  /**
   * @param cctx Context.
   * @param id Partition ID.
   */
  @SuppressWarnings("ExternalizableWithoutPublicNoArgConstructor")
  GridDhtLocalPartition(GridCacheContext cctx, int id) {
    assert cctx != null;

    this.id = id;
    this.cctx = cctx;

    log = U.logger(cctx.kernalContext(), logRef, this);

    rent =
        new GridFutureAdapter<Object>() {
          @Override
          public String toString() {
            return "PartitionRentFuture [part=" + GridDhtLocalPartition.this + ", map=" + map + ']';
          }
        };

    map = new ConcurrentHashMap8<>(cctx.config().getStartSize() / cctx.affinity().partitions());

    int delQueueSize =
        CU.isSystemCache(cctx.name())
            ? 100
            : Math.max(MAX_DELETE_QUEUE_SIZE / cctx.affinity().partitions(), 20);

    rmvQueue = new GridCircularBuffer<>(U.ceilPow2(delQueueSize));
  }

  /**
   * 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);
  }

  /** @param r Reservation. */
  public void removeReservation(GridDhtPartitionsReservation r) {
    if (!reservations.remove(r))
      throw new IllegalStateException("Reservation was already removed.");
  }

  /** @return Partition ID. */
  public int id() {
    return id;
  }

  /** @return Create time. */
  long createTime() {
    return createTime;
  }

  /** @return Partition state. */
  public GridDhtPartitionState state() {
    return state.getReference();
  }

  /** @return Reservations. */
  public int reservations() {
    return state.getStamp();
  }

  /** @return Keys belonging to partition. */
  public Set<KeyCacheObject> keySet() {
    return map.keySet();
  }

  /** @return Entries belonging to partition. */
  public Collection<GridDhtCacheEntry> entries() {
    return map.values();
  }

  /** @return {@code True} if partition is empty. */
  public boolean isEmpty() {
    return map.isEmpty();
  }

  /** @return Number of entries in this partition (constant-time method). */
  public int size() {
    return map.size();
  }

  /** Increments public size of the map. */
  public void incrementPublicSize() {
    mapPubSize.increment();
  }

  /** Decrements public size of the map. */
  public void decrementPublicSize() {
    mapPubSize.decrement();
  }

  /** @return Number of public (non-internal) entries in this partition. */
  public int publicSize() {
    return mapPubSize.intValue();
  }

  /** @return If partition is moving or owning or renting. */
  public boolean valid() {
    GridDhtPartitionState state = state();

    return state == MOVING || state == OWNING || state == RENTING;
  }

  /** @param entry Entry to add. */
  void onAdded(GridDhtCacheEntry entry) {
    GridDhtPartitionState state = state();

    if (state == EVICTED)
      throw new GridDhtInvalidPartitionException(
          id, "Adding entry to invalid partition [part=" + id + ']');

    map.put(entry.key(), entry);

    if (!entry.isInternal()) mapPubSize.increment();
  }

  /** @param entry Entry to remove. */
  @SuppressWarnings("SynchronizationOnLocalVariableOrMethodParameter")
  void onRemoved(GridDhtCacheEntry entry) {
    assert entry.obsolete();

    // Make sure to remove exactly this entry.
    synchronized (entry) {
      map.remove(entry.key(), entry);

      if (!entry.isInternal() && !entry.deleted()) mapPubSize.decrement();
    }

    // Attempt to evict.
    tryEvict(true);
  }

  /**
   * @param key Removed key.
   * @param ver Removed version.
   * @throws IgniteCheckedException If failed.
   */
  public void onDeferredDelete(KeyCacheObject key, GridCacheVersion ver)
      throws IgniteCheckedException {
    try {
      T2<KeyCacheObject, GridCacheVersion> evicted = rmvQueue.add(new T2<>(key, ver));

      if (evicted != null) cctx.dht().removeVersionedEntry(evicted.get1(), evicted.get2());
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();

      throw new IgniteInterruptedCheckedException(e);
    }
  }

  /** Locks partition. */
  @SuppressWarnings({"LockAcquiredButNotSafelyReleased"})
  public void lock() {
    lock.lock();
  }

  /** Unlocks partition. */
  public void unlock() {
    lock.unlock();
  }

  /**
   * @param key Key.
   * @param ver Version.
   */
  public void onEntryEvicted(KeyCacheObject key, GridCacheVersion ver) {
    assert key != null;
    assert ver != null;
    assert lock.isHeldByCurrentThread(); // Only one thread can enter this method at a time.

    if (state() != MOVING) return;

    Map<KeyCacheObject, GridCacheVersion> evictHist0 = evictHist;

    if (evictHist0 != null) {
      GridCacheVersion ver0 = evictHist0.get(key);

      if (ver0 == null || ver0.isLess(ver)) {
        GridCacheVersion ver1 = evictHist0.put(key, ver);

        assert ver1 == ver0;
      }
    }
  }

  /**
   * Cache preloader should call this method within partition lock.
   *
   * @param key Key.
   * @param ver Version.
   * @return {@code True} if preloading is permitted.
   */
  public boolean preloadingPermitted(KeyCacheObject key, GridCacheVersion ver) {
    assert key != null;
    assert ver != null;
    assert lock.isHeldByCurrentThread(); // Only one thread can enter this method at a time.

    if (state() != MOVING) return false;

    Map<KeyCacheObject, GridCacheVersion> evictHist0 = evictHist;

    if (evictHist0 != null) {
      GridCacheVersion ver0 = evictHist0.get(key);

      // Permit preloading if version in history
      // is missing or less than passed in.
      return ver0 == null || ver0.isLess(ver);
    }

    return false;
  }

  /**
   * 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;
    }
  }

  /** 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;
      }
    }
  }

  /** @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;
      }
    }
  }

  /**
   * @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;
  }

  /**
   * @param updateSeq Update sequence.
   * @return Future for evict attempt.
   */
  IgniteInternalFuture<Boolean> tryEvictAsync(boolean updateSeq) {
    if (map.isEmpty()
        && !GridQueryProcessor.isEnabled(cctx.config())
        && state.compareAndSet(RENTING, EVICTED, 0, 0)) {
      if (log.isDebugEnabled()) log.debug("Evicted partition: " + this);

      clearSwap();

      if (cctx.isDrEnabled()) cctx.dr().partitionEvicted(id);

      cctx.dataStructures().onPartitionEvicted(id);

      rent.onDone();

      ((GridDhtPreloader) cctx.preloader()).onPartitionEvicted(this, updateSeq);

      clearDeferredDeletes();

      return new GridFinishedFuture<>(true);
    }

    return cctx.closures()
        .callLocalSafe(
            new GPC<Boolean>() {
              @Override
              public Boolean call() {
                return tryEvict(true);
              }
            }, /*system pool*/
            true);
  }

  /** @return {@code true} If there is a group reservation. */
  private boolean groupReserved() {
    for (GridDhtPartitionsReservation reservation : reservations) {
      if (!reservation.invalidate())
        return true; // Failed to invalidate reservation -> we are reserved.
    }

    return false;
  }

  /**
   * @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;
  }

  /** Clears swap entries for evicted partition. */
  private void clearSwap() {
    assert state() == EVICTED;
    assert !GridQueryProcessor.isEnabled(cctx.config())
        : "Indexing needs to have unswapped values.";

    try {
      GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> it = cctx.swap().iterator(id);

      boolean isLocStore = cctx.store().isLocal();

      if (it != null) {
        // We can safely remove these values because no entries will be created for evicted
        // partition.
        while (it.hasNext()) {
          Map.Entry<byte[], GridCacheSwapEntry> entry = it.next();

          byte[] keyBytes = entry.getKey();

          KeyCacheObject key = cctx.toCacheKeyObject(keyBytes);

          cctx.swap().remove(key);

          if (isLocStore) cctx.store().remove(null, key.value(cctx.cacheObjectContext(), false));
        }
      }
    } catch (IgniteCheckedException e) {
      U.error(log, "Failed to clear swap for evicted partition: " + this, e);
    }
  }

  /** */
  void onUnlock() {
    tryEvict(true);
  }

  /**
   * @param topVer Topology version.
   * @return {@code True} if local node is primary for this partition.
   */
  public boolean primary(AffinityTopologyVersion topVer) {
    return cctx.affinity().primary(cctx.localNode(), id, topVer);
  }

  /** Clears values for this partition. */
  private void clearAll() {
    GridCacheVersion clearVer = cctx.versions().next();

    boolean swap = cctx.isSwapOrOffheapEnabled();

    boolean rec = cctx.events().isRecordable(EVT_CACHE_REBALANCE_OBJECT_UNLOADED);

    Iterator<GridDhtCacheEntry> it = map.values().iterator();

    GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> swapIt = null;

    if (swap
        && GridQueryProcessor.isEnabled(cctx.config())) { // Indexing needs to unswap cache values.
      Iterator<GridDhtCacheEntry> unswapIt = null;

      try {
        swapIt = cctx.swap().iterator(id);
        unswapIt = unswapIterator(swapIt);
      } catch (Exception e) {
        U.error(log, "Failed to clear swap for evicted partition: " + this, e);
      }

      if (unswapIt != null) it = F.concat(it, unswapIt);
    }

    try {
      while (it.hasNext()) {
        GridDhtCacheEntry cached = it.next();

        try {
          if (cached.clearInternal(clearVer, swap)) {
            map.remove(cached.key(), cached);

            if (!cached.isInternal()) {
              mapPubSize.decrement();

              if (rec)
                cctx.events()
                    .addEvent(
                        cached.partition(),
                        cached.key(),
                        cctx.localNodeId(),
                        (IgniteUuid) null,
                        null,
                        EVT_CACHE_REBALANCE_OBJECT_UNLOADED,
                        null,
                        false,
                        cached.rawGet(),
                        cached.hasValue(),
                        null,
                        null,
                        null);
            }
          }
        } catch (IgniteCheckedException e) {
          U.error(log, "Failed to clear cache entry for evicted partition: " + cached, e);
        }
      }
    } finally {
      U.close(swapIt, log);
    }
  }

  /**
   * @param it Swap iterator.
   * @return Unswapping iterator over swapped entries.
   */
  private Iterator<GridDhtCacheEntry> unswapIterator(
      final GridCloseableIterator<Map.Entry<byte[], GridCacheSwapEntry>> it) {
    if (it == null) return null;

    return new Iterator<GridDhtCacheEntry>() {
      /** */
      GridDhtCacheEntry lastEntry;

      @Override
      public boolean hasNext() {
        return it.hasNext();
      }

      @Override
      public GridDhtCacheEntry next() {
        Map.Entry<byte[], GridCacheSwapEntry> entry = it.next();

        byte[] keyBytes = entry.getKey();

        try {
          KeyCacheObject key = cctx.toCacheKeyObject(keyBytes);

          lastEntry = (GridDhtCacheEntry) cctx.cache().entryEx(key, false);

          lastEntry.unswap(true);

          return lastEntry;
        } catch (IgniteCheckedException e) {
          throw new CacheException(e);
        }
      }

      @Override
      public void remove() {
        map.remove(lastEntry.key(), lastEntry);
      }
    };
  }

  /** */
  private void clearDeferredDeletes() {
    rmvQueue.forEach(
        new CI1<T2<KeyCacheObject, GridCacheVersion>>() {
          @Override
          public void apply(T2<KeyCacheObject, GridCacheVersion> t) {
            cctx.dht().removeVersionedEntry(t.get1(), t.get2());
          }
        });
  }

  /** {@inheritDoc} */
  @Override
  public int hashCode() {
    return id;
  }

  /** {@inheritDoc} */
  @SuppressWarnings({"OverlyStrongTypeCast"})
  @Override
  public boolean equals(Object obj) {
    return obj instanceof GridDhtLocalPartition
        && (obj == this || ((GridDhtLocalPartition) obj).id() == id);
  }

  /** {@inheritDoc} */
  @Override
  public int compareTo(@NotNull GridDhtLocalPartition part) {
    if (part == null) return 1;

    return Integer.compare(id, part.id());
  }

  /** {@inheritDoc} */
  @Override
  public String toString() {
    return S.toString(
        GridDhtLocalPartition.class,
        this,
        "state",
        state(),
        "reservations",
        reservations(),
        "empty",
        map.isEmpty(),
        "createTime",
        U.format(createTime),
        "mapPubSize",
        mapPubSize);
  }
}
  /** {@inheritDoc} */
  @Override
  public long duration() {
    long endTime = this.endTime;

    return endTime == 0 ? U.currentTimeMillis() - startTime : endTime - startTime;
  }
/** Future adapter. */
public class GridFutureAdapter<R> extends AbstractQueuedSynchronizer
    implements IgniteInternalFuture<R> {
  /** */
  private static final long serialVersionUID = 0L;

  /** Initial state. */
  private static final int INIT = 0;

  /** Cancelled state. */
  private static final int CANCELLED = 1;

  /** Done state. */
  private static final int DONE = 2;

  /** */
  private static final byte ERR = 1;

  /** */
  private static final byte RES = 2;

  /** */
  private byte resFlag;

  /** Result. */
  @GridToStringInclude private Object res;

  /** Future start time. */
  private final long startTime = U.currentTimeMillis();

  /** Future end time. */
  private volatile long endTime;

  /** */
  private boolean ignoreInterrupts;

  /** */
  private IgniteInClosure<? super IgniteInternalFuture<R>> lsnr;

  /** {@inheritDoc} */
  @Override
  public long startTime() {
    return startTime;
  }

  /** {@inheritDoc} */
  @Override
  public long duration() {
    long endTime = this.endTime;

    return endTime == 0 ? U.currentTimeMillis() - startTime : endTime - startTime;
  }

  /** @param ignoreInterrupts Ignore interrupts flag. */
  public void ignoreInterrupts(boolean ignoreInterrupts) {
    this.ignoreInterrupts = ignoreInterrupts;
  }

  /** @return Future end time. */
  public long endTime() {
    return endTime;
  }

  /** {@inheritDoc} */
  @Override
  public Throwable error() {
    return (resFlag == ERR) ? (Throwable) res : null;
  }

  /** {@inheritDoc} */
  @Override
  public R result() {
    return resFlag == RES ? (R) res : null;
  }

  /** {@inheritDoc} */
  @Override
  public R get() throws IgniteCheckedException {
    try {
      if (endTime == 0) {
        if (ignoreInterrupts) acquireShared(0);
        else acquireSharedInterruptibly(0);
      }

      if (getState() == CANCELLED)
        throw new IgniteFutureCancelledCheckedException("Future was cancelled: " + this);

      assert resFlag != 0;

      if (resFlag == ERR) throw U.cast((Throwable) res);

      return (R) res;
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();

      throw new IgniteInterruptedCheckedException(e);
    }
  }

  /** {@inheritDoc} */
  @Override
  public R get(long timeout) throws IgniteCheckedException {
    // Do not replace with static import, as it may not compile.
    return get(timeout, TimeUnit.MILLISECONDS);
  }

  /** {@inheritDoc} */
  @Override
  public R get(long timeout, TimeUnit unit) throws IgniteCheckedException {
    A.ensure(timeout >= 0, "timeout cannot be negative: " + timeout);
    A.notNull(unit, "unit");

    try {
      return get0(unit.toNanos(timeout));
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();

      throw new IgniteInterruptedCheckedException(
          "Got interrupted while waiting for future to complete.", e);
    }
  }

  /**
   * @param nanosTimeout Timeout (nanoseconds).
   * @return Result.
   * @throws InterruptedException If interrupted.
   * @throws IgniteFutureTimeoutCheckedException If timeout reached before computation completed.
   * @throws IgniteCheckedException If error occurred.
   */
  @Nullable
  protected R get0(long nanosTimeout) throws InterruptedException, IgniteCheckedException {
    if (endTime == 0 && !tryAcquireSharedNanos(0, nanosTimeout))
      throw new IgniteFutureTimeoutCheckedException(
          "Timeout was reached before computation completed.");

    if (getState() == CANCELLED)
      throw new IgniteFutureCancelledCheckedException("Future was cancelled: " + this);

    assert resFlag != 0;

    if (resFlag == ERR) throw U.cast((Throwable) res);

    return (R) res;
  }

  /** {@inheritDoc} */
  @Override
  public void listen(IgniteInClosure<? super IgniteInternalFuture<R>> lsnr0) {
    assert lsnr0 != null;

    boolean done = isDone();

    if (!done) {
      synchronized (this) {
        done = isDone(); // Double check.

        if (!done) {
          if (lsnr == null) lsnr = lsnr0;
          else if (lsnr instanceof ArrayListener) ((ArrayListener) lsnr).add(lsnr0);
          else {
            lsnr = (IgniteInClosure) new ArrayListener<IgniteInternalFuture>(lsnr, lsnr0);
          }

          return;
        }
      }
    }

    assert done;

    notifyListener(lsnr0);
  }

  /** {@inheritDoc} */
  @Override
  public <T> IgniteInternalFuture<T> chain(
      final IgniteClosure<? super IgniteInternalFuture<R>, T> doneCb) {
    return new ChainFuture<>(this, doneCb);
  }

  /** Notifies all registered listeners. */
  private void notifyListeners() {
    IgniteInClosure<? super IgniteInternalFuture<R>> lsnr0;

    synchronized (this) {
      lsnr0 = lsnr;

      if (lsnr0 == null) return;

      lsnr = null;
    }

    assert lsnr0 != null;

    notifyListener(lsnr0);
  }

  /**
   * Notifies single listener.
   *
   * @param lsnr Listener.
   */
  private void notifyListener(IgniteInClosure<? super IgniteInternalFuture<R>> lsnr) {
    assert lsnr != null;

    try {
      lsnr.apply(this);
    } catch (IllegalStateException e) {
      U.error(
          null,
          "Failed to notify listener (is grid stopped?) [fut="
              + this
              + ", lsnr="
              + lsnr
              + ", err="
              + e.getMessage()
              + ']',
          e);
    } catch (RuntimeException | Error e) {
      U.error(null, "Failed to notify listener: " + lsnr, e);

      throw e;
    }
  }

  /**
   * Default no-op implementation that always returns {@code false}. Futures that do support
   * cancellation should override this method and call {@link #onCancelled()} callback explicitly if
   * cancellation indeed did happen.
   */
  @Override
  public boolean cancel() throws IgniteCheckedException {
    return false;
  }

  /** {@inheritDoc} */
  @Override
  public boolean isDone() {
    // Don't check for "valid" here, as "done" flag can be read
    // even in invalid state.
    return endTime != 0;
  }

  /** @return Checks is future is completed with exception. */
  public boolean isFailed() {
    // Must read endTime first.
    return endTime != 0 && resFlag == ERR;
  }

  /** {@inheritDoc} */
  @Override
  public boolean isCancelled() {
    return getState() == CANCELLED;
  }

  /**
   * Callback to notify that future is finished with {@code null} result. This method must delegate
   * to {@link #onDone(Object, Throwable)} method.
   *
   * @return {@code True} if result was set by this call.
   */
  public final boolean onDone() {
    return onDone(null, null);
  }

  /**
   * Callback to notify that future is finished. This method must delegate to {@link #onDone(Object,
   * Throwable)} method.
   *
   * @param res Result.
   * @return {@code True} if result was set by this call.
   */
  public final boolean onDone(@Nullable R res) {
    return onDone(res, null);
  }

  /**
   * Callback to notify that future is finished. This method must delegate to {@link #onDone(Object,
   * Throwable)} method.
   *
   * @param err Error.
   * @return {@code True} if result was set by this call.
   */
  public final boolean onDone(@Nullable Throwable err) {
    return onDone(null, err);
  }

  /**
   * Callback to notify that future is finished. Note that if non-{@code null} exception is passed
   * in the result value will be ignored.
   *
   * @param res Optional result.
   * @param err Optional error.
   * @return {@code True} if result was set by this call.
   */
  public boolean onDone(@Nullable R res, @Nullable Throwable err) {
    return onDone(res, err, false);
  }

  /**
   * @param res Result.
   * @param err Error.
   * @param cancel {@code True} if future is being cancelled.
   * @return {@code True} if result was set by this call.
   */
  private boolean onDone(@Nullable R res, @Nullable Throwable err, boolean cancel) {
    boolean notify = false;

    try {
      if (compareAndSetState(INIT, cancel ? CANCELLED : DONE)) {
        if (err != null) {
          resFlag = ERR;
          this.res = err;
        } else {
          resFlag = RES;
          this.res = res;
        }

        notify = true;

        releaseShared(0);

        return true;
      }

      return false;
    } finally {
      if (notify) notifyListeners();
    }
  }

  /**
   * Callback to notify that future is cancelled.
   *
   * @return {@code True} if cancel flag was set by this call.
   */
  public boolean onCancelled() {
    return onDone(null, null, true);
  }

  /** {@inheritDoc} */
  @Override
  protected final int tryAcquireShared(int ignore) {
    return endTime != 0 ? 1 : -1;
  }

  /** {@inheritDoc} */
  @Override
  protected final boolean tryReleaseShared(int ignore) {
    endTime = U.currentTimeMillis();

    // Always signal after setting final done status.
    return true;
  }

  /** @return String representation of state. */
  private String state() {
    int s = getState();

    return s == INIT ? "INIT" : s == CANCELLED ? "CANCELLED" : "DONE";
  }

  /** {@inheritDoc} */
  @Override
  public String toString() {
    return S.toString(GridFutureAdapter.class, this, "state", state());
  }

  /** */
  private static class ArrayListener<R> implements IgniteInClosure<IgniteInternalFuture<R>> {
    /** */
    private static final long serialVersionUID = 0L;

    /** */
    private IgniteInClosure<? super IgniteInternalFuture<R>>[] arr;

    /** @param lsnrs Listeners. */
    private ArrayListener(IgniteInClosure... lsnrs) {
      this.arr = lsnrs;
    }

    /** {@inheritDoc} */
    @Override
    public void apply(IgniteInternalFuture<R> fut) {
      for (int i = 0; i < arr.length; i++) arr[i].apply(fut);
    }

    /** @param lsnr Listener. */
    void add(IgniteInClosure<? super IgniteInternalFuture<R>> lsnr) {
      arr = Arrays.copyOf(arr, arr.length + 1);

      arr[arr.length - 1] = lsnr;
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
      return S.toString(ArrayListener.class, this, "arrSize", arr.length);
    }
  }

  /** */
  private static class ChainFuture<R, T> extends GridFutureAdapter<T> {
    /** */
    private static final long serialVersionUID = 0L;

    /** */
    private GridFutureAdapter<R> fut;

    /** */
    private IgniteClosure<? super IgniteInternalFuture<R>, T> doneCb;

    /** */
    public ChainFuture() {
      // No-op.
    }

    /**
     * @param fut Future.
     * @param doneCb Closure.
     */
    ChainFuture(
        GridFutureAdapter<R> fut, IgniteClosure<? super IgniteInternalFuture<R>, T> doneCb) {
      this.fut = fut;
      this.doneCb = doneCb;

      fut.listen(new GridFutureChainListener<>(this, doneCb));
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
      return "ChainFuture [orig=" + fut + ", doneCb=" + doneCb + ']';
    }
  }
}