/** @param e Error. */
  void onError(Throwable e) {
    tx.commitError(e);

    if (err.compareAndSet(null, e)) {
      boolean marked = tx.setRollbackOnly();

      if (e instanceof GridCacheTxRollbackException) {
        if (marked) {
          try {
            tx.rollback();
          } catch (GridException ex) {
            U.error(log, "Failed to automatically rollback transaction: " + tx, ex);
          }
        }
      } else if (tx.implicit()
          && tx.isSystemInvalidate()) { // Finish implicit transaction on heuristic error.
        try {
          tx.close();
        } catch (GridException ex) {
          U.error(log, "Failed to invalidate transaction: " + tx, ex);
        }
      }

      onComplete();
    }
  }
  /** Initializes future. */
  @SuppressWarnings({"unchecked"})
  void finish() {
    if (mappings != null) {
      finish(mappings.values());

      markInitialized();

      if (!isSync()) {
        boolean complete = true;

        for (GridFuture<?> f : pending())
          // Mini-future in non-sync mode gets done when message gets sent.
          if (isMini(f) && !f.isDone()) complete = false;

        if (complete) onComplete();
      }
    } else {
      assert !commit;

      try {
        tx.rollback();
      } catch (GridException e) {
        U.error(log, "Failed to rollback empty transaction: " + tx, e);
      }

      markInitialized();
    }
  }
  /** {@inheritDoc} */
  @Override
  public boolean onDone(GridCacheTx tx, Throwable err) {
    if ((initialized() || err != null) && super.onDone(tx, err)) {
      if (error() instanceof GridCacheTxHeuristicException) {
        long topVer = this.tx.topologyVersion();

        for (GridCacheTxEntry<K, V> e : this.tx.writeMap().values()) {
          try {
            if (e.op() != NOOP && !cctx.affinity().localNode(e.key(), topVer)) {
              GridCacheEntryEx<K, V> cacheEntry = cctx.cache().peekEx(e.key());

              if (cacheEntry != null) cacheEntry.invalidate(null, this.tx.xidVersion());
            }
          } catch (Throwable t) {
            U.error(log, "Failed to invalidate entry.", t);

            if (t instanceof Error) throw (Error) t;
          }
        }
      }

      // Don't forget to clean up.
      cctx.mvcc().removeFuture(this);

      return true;
    }

    return false;
  }
  /** @param e Error. */
  void onError(Throwable e) {
    tx.commitError(e);

    if (err.compareAndSet(null, e)) {
      boolean marked = tx.setRollbackOnly();

      if (e instanceof GridCacheTxRollbackException)
        if (marked) {
          try {
            tx.rollback();
          } catch (GridException ex) {
            U.error(log, "Failed to automatically rollback transaction: " + tx, ex);
          }
        }

      onComplete();
    }
  }
  /**
   * Removes locks regardless of whether they are owned or not for given version and keys.
   *
   * @param ver Lock version.
   * @param keys Keys.
   */
  @SuppressWarnings({"unchecked"})
  public void removeLocks(GridCacheVersion ver, Collection<? extends K> keys) {
    if (keys.isEmpty()) return;

    try {
      Collection<GridRichNode> affNodes = null;

      int keyCnt = -1;

      Map<GridNode, GridNearUnlockRequest<K, V>> map = null;

      for (K key : keys) {
        // Send request to remove from remote nodes.
        GridNearUnlockRequest<K, V> req = null;

        while (true) {
          GridDistributedCacheEntry<K, V> entry = peekExx(key);

          try {
            if (entry != null) {
              GridCacheMvccCandidate<K> cand = entry.candidate(ver);

              if (cand != null) {
                if (affNodes == null) {
                  affNodes = CU.allNodes(ctx, cand.topologyVersion());

                  keyCnt = (int) Math.ceil((double) keys.size() / affNodes.size());

                  map = new HashMap<GridNode, GridNearUnlockRequest<K, V>>(affNodes.size());
                }

                GridRichNode primary = CU.primary0(ctx.affinity(key, affNodes));

                if (!primary.isLocal()) {
                  req = map.get(primary);

                  if (req == null) {
                    map.put(primary, req = new GridNearUnlockRequest<K, V>(keyCnt));

                    req.version(ver);
                  }
                }

                // Remove candidate from local node first.
                if (entry.removeLock(cand.version())) {
                  if (primary.isLocal()) {
                    dht.removeLocks(primary.id(), ver, F.asList(key), true);

                    assert req == null;

                    continue;
                  }

                  req.addKey(entry.key(), entry.getOrMarshalKeyBytes(), ctx);
                }
              }
            }

            break;
          } catch (GridCacheEntryRemovedException ignored) {
            if (log.isDebugEnabled())
              log.debug(
                  "Attempted to remove lock from removed entry (will retry) [rmvVer="
                      + ver
                      + ", entry="
                      + entry
                      + ']');
          }
        }
      }

      if (map == null || map.isEmpty()) return;

      Collection<GridCacheVersion> committed = ctx.tm().committedVersions(ver);
      Collection<GridCacheVersion> rolledback = ctx.tm().rolledbackVersions(ver);

      for (Map.Entry<GridNode, GridNearUnlockRequest<K, V>> mapping : map.entrySet()) {
        GridNode n = mapping.getKey();

        GridDistributedUnlockRequest<K, V> req = mapping.getValue();

        if (!req.keyBytes().isEmpty()) {
          req.completedVersions(committed, rolledback);

          // We don't wait for reply to this message.
          ctx.io().send(n, req);
        }
      }
    } catch (GridException ex) {
      U.error(log, "Failed to unlock the lock for keys: " + keys, ex);
    }
  }
  /** {@inheritDoc} */
  @Override
  public void unlockAll(
      Collection<? extends K> keys, GridPredicate<? super GridCacheEntry<K, V>>[] filter) {
    if (keys.isEmpty()) return;

    try {
      GridCacheVersion ver = null;

      Collection<GridRichNode> affNodes = null;

      int keyCnt = -1;

      Map<GridRichNode, GridNearUnlockRequest<K, V>> map = null;

      Collection<K> locKeys = new LinkedList<K>();

      GridCacheVersion obsoleteVer = ctx.versions().next();

      for (K key : keys) {
        while (true) {
          GridDistributedCacheEntry<K, V> entry = peekExx(key);

          if (entry == null || !ctx.isAll(entry.wrap(false), filter)) break; // While.

          try {
            GridCacheMvccCandidate<K> cand =
                entry.candidate(ctx.nodeId(), Thread.currentThread().getId());

            if (cand != null) {
              ver = cand.version();

              if (affNodes == null) {
                affNodes = CU.allNodes(ctx, cand.topologyVersion());

                keyCnt = (int) Math.ceil((double) keys.size() / affNodes.size());

                map = new HashMap<GridRichNode, GridNearUnlockRequest<K, V>>(affNodes.size());
              }

              // Send request to remove from remote nodes.
              GridRichNode primary = CU.primary0(ctx.affinity(key, affNodes));

              GridNearUnlockRequest<K, V> req = map.get(primary);

              if (req == null) {
                map.put(primary, req = new GridNearUnlockRequest<K, V>(keyCnt));

                req.version(ver);
              }

              // Remove candidate from local node first.
              GridCacheMvccCandidate<K> rmv = entry.removeLock();

              if (rmv != null) {
                if (!rmv.reentry()) {
                  if (ver != null && !ver.equals(rmv.version()))
                    throw new GridException(
                        "Failed to unlock (if keys were locked separately, "
                            + "then they need to be unlocked separately): "
                            + keys);

                  if (!primary.isLocal()) {
                    assert req != null;

                    req.addKey(entry.key(), entry.getOrMarshalKeyBytes(), ctx);
                  } else locKeys.add(key);

                  if (log.isDebugEnabled()) log.debug("Removed lock (will distribute): " + rmv);
                } else if (log.isDebugEnabled())
                  log.debug(
                      "Current thread still owns lock (or there are no other nodes)"
                          + " [lock="
                          + rmv
                          + ", curThreadId="
                          + Thread.currentThread().getId()
                          + ']');
              }

              // Try to evict near entry if it's dht-mapped locally.
              evictNearEntry(entry, obsoleteVer);
            }

            break;
          } catch (GridCacheEntryRemovedException ignore) {
            if (log.isDebugEnabled())
              log.debug("Attempted to unlock removed entry (will retry): " + entry);
          }
        }
      }

      if (ver == null) return;

      for (Map.Entry<GridRichNode, GridNearUnlockRequest<K, V>> mapping : map.entrySet()) {
        GridRichNode n = mapping.getKey();

        GridDistributedUnlockRequest<K, V> req = mapping.getValue();

        if (n.isLocal()) dht.removeLocks(ctx.nodeId(), req.version(), locKeys, true);
        else if (!req.keyBytes().isEmpty())
          // We don't wait for reply to this message.
          ctx.io().send(n, req);
      }
    } catch (GridException ex) {
      U.error(log, "Failed to unlock the lock for keys: " + keys, ex);
    }
  }