/** {@inheritDoc} */
  @Override
  public GridDiscoveryTopologySnapshot topologySnapshot() throws IgniteCheckedException {
    get();

    if (topSnapshot.get() == null)
      topSnapshot.compareAndSet(
          null,
          new GridDiscoveryTopologySnapshot(discoEvt.topologyVersion(), discoEvt.topologyNodes()));

    return topSnapshot.get();
  }
  /**
   * @param nodes Nodes.
   * @param id ID.
   * @throws IgniteCheckedException If failed.
   */
  private void sendAllPartitions(
      Collection<? extends ClusterNode> nodes, GridDhtPartitionExchangeId id)
      throws IgniteCheckedException {
    GridDhtPartitionsFullMessage m =
        new GridDhtPartitionsFullMessage(id, lastVer.get(), id.topologyVersion());

    for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
      if (!cacheCtx.isLocal()) {
        AffinityTopologyVersion startTopVer = cacheCtx.startTopologyVersion();

        boolean ready = startTopVer == null || startTopVer.compareTo(id.topologyVersion()) <= 0;

        if (ready)
          m.addFullPartitionsMap(cacheCtx.cacheId(), cacheCtx.topology().partitionMap(true));
      }
    }

    // It is important that client topologies be added after contexts.
    for (GridClientPartitionTopology top : cctx.exchange().clientTopologies())
      m.addFullPartitionsMap(top.cacheId(), top.partitionMap(true));

    if (log.isDebugEnabled())
      log.debug(
          "Sending full partition map [nodeIds="
              + F.viewReadOnly(nodes, F.node2id())
              + ", exchId="
              + exchId
              + ", msg="
              + m
              + ']');

    cctx.io().safeSend(nodes, m, SYSTEM_POOL, null);
  }
  /** @param evts Events to add. */
  private void addAll(Collection<E> evts) {
    WindowHolder tup = ref.get();

    int cnt = addAllInternal(evts, tup.collection(), tup.set());

    tup.size().addAndGet(cnt);
  }
  private void recheck() {
    // If this is the oldest node.
    if (oldestNode.get().id().equals(cctx.localNodeId())) {
      Collection<UUID> remaining = remaining();

      if (!remaining.isEmpty()) {
        try {
          cctx.io()
              .safeSend(
                  cctx.discovery().nodes(remaining),
                  new GridDhtPartitionsSingleRequest(exchId),
                  SYSTEM_POOL,
                  null);
        } catch (IgniteCheckedException e) {
          U.error(
              log,
              "Failed to request partitions from nodes [exchangeId="
                  + exchId
                  + ", nodes="
                  + remaining
                  + ']',
              e);
        }
      }
      // Resend full partition map because last attempt failed.
      else {
        if (spreadPartitions()) onDone(exchId.topologyVersion());
      }
    } else sendPartitions();

    // Schedule another send.
    scheduleRecheck();
  }
Пример #5
0
  /**
   * Completeness callback.
   *
   * @param success {@code True} if lock was acquired.
   * @param distribute {@code True} if need to distribute lock removal in case of failure.
   * @return {@code True} if complete by this operation.
   */
  private boolean onComplete(boolean success, boolean distribute) {
    if (log.isDebugEnabled())
      log.debug(
          "Received onComplete(..) callback [success="
              + success
              + ", distribute="
              + distribute
              + ", fut="
              + this
              + ']');

    if (!success) undoLocks(distribute);

    if (tx != null) cctx.tm().txContext(tx);

    if (super.onDone(success, err.get())) {
      if (log.isDebugEnabled()) log.debug("Completing future: " + this);

      // Clean up.
      cctx.mvcc().removeFuture(this);

      if (timeoutObj != null) cctx.time().removeTimeoutObject(timeoutObj);

      return true;
    }

    return false;
  }
  /** {@inheritDoc} */
  @Override
  protected Collection<E> dequeue0(int cnt) {
    WindowHolder tup = ref.get();

    AtomicInteger size = tup.size();
    Collection<T> evts = tup.collection();

    Collection<E> resCol = new ArrayList<>(cnt);

    while (true) {
      int curSize = size.get();

      if (curSize > 0) {
        if (size.compareAndSet(curSize, curSize - 1)) {
          E res = pollInternal(evts, tup.set());

          if (res != null) {
            resCol.add(res);

            if (resCol.size() >= cnt) return resCol;
          } else {
            size.incrementAndGet();

            return resCol;
          }
        }
      } else return resCol;
    }
  }
  /**
   * Poll evicted internal implementation.
   *
   * @return Evicted element.
   */
  @Nullable
  private E pollEvictedInternal() {
    WindowHolder tup = ref.get();

    AtomicInteger size = tup.size();

    while (true) {
      int curSize = size.get();

      if (curSize > maxSize) {
        if (size.compareAndSet(curSize, curSize - 1)) {
          E evt = pollInternal(tup.collection(), tup.set());

          if (evt != null) return evt;
          else {
            // No actual events in queue, it means that other thread is just adding event.
            // return null as it is a concurrent add call.
            size.incrementAndGet();

            return null;
          }
        }
      } else return null;
    }
  }
  /**
   * Starts activity.
   *
   * @throws IgniteInterruptedCheckedException If interrupted.
   */
  public void init() throws IgniteInterruptedCheckedException {
    if (isDone()) return;

    if (init.compareAndSet(false, true)) {
      if (isDone()) return;

      try {
        // Wait for event to occur to make sure that discovery
        // will return corresponding nodes.
        U.await(evtLatch);

        assert discoEvt != null : this;
        assert !dummy && !forcePreload : this;

        ClusterNode oldest = CU.oldestAliveCacheServerNode(cctx, exchId.topologyVersion());

        oldestNode.set(oldest);

        startCaches();

        // True if client node joined or failed.
        boolean clientNodeEvt;

        if (F.isEmpty(reqs)) {
          int type = discoEvt.type();

          assert type == EVT_NODE_JOINED || type == EVT_NODE_LEFT || type == EVT_NODE_FAILED
              : discoEvt;

          clientNodeEvt = CU.clientNode(discoEvt.eventNode());
        } else {
          assert discoEvt.type() == EVT_DISCOVERY_CUSTOM_EVT : discoEvt;

          boolean clientOnlyStart = true;

          for (DynamicCacheChangeRequest req : reqs) {
            if (!req.clientStartOnly()) {
              clientOnlyStart = false;

              break;
            }
          }

          clientNodeEvt = clientOnlyStart;
        }

        if (clientNodeEvt) {
          ClusterNode node = discoEvt.eventNode();

          // Client need to initialize affinity for local join event or for stated client caches.
          if (!node.isLocal()) {
            for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
              if (cacheCtx.isLocal()) continue;

              GridDhtPartitionTopology top = cacheCtx.topology();

              top.updateTopologyVersion(exchId, this, -1, stopping(cacheCtx.cacheId()));

              if (cacheCtx.affinity().affinityTopologyVersion() == AffinityTopologyVersion.NONE) {
                initTopology(cacheCtx);

                top.beforeExchange(this);
              } else
                cacheCtx.affinity().clientEventTopologyChange(discoEvt, exchId.topologyVersion());
            }

            if (exchId.isLeft())
              cctx.mvcc().removeExplicitNodeLocks(exchId.nodeId(), exchId.topologyVersion());

            onDone(exchId.topologyVersion());

            skipPreload = cctx.kernalContext().clientNode();

            return;
          }
        }

        if (cctx.kernalContext().clientNode()) {
          skipPreload = true;

          for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
            if (cacheCtx.isLocal()) continue;

            GridDhtPartitionTopology top = cacheCtx.topology();

            top.updateTopologyVersion(exchId, this, -1, stopping(cacheCtx.cacheId()));
          }

          for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
            if (cacheCtx.isLocal()) continue;

            initTopology(cacheCtx);
          }

          if (oldestNode.get() != null) {
            rmtNodes =
                new ConcurrentLinkedQueue<>(
                    CU.aliveRemoteServerNodesWithCaches(cctx, exchId.topologyVersion()));

            rmtIds = Collections.unmodifiableSet(new HashSet<>(F.nodeIds(rmtNodes)));

            ready.set(true);

            initFut.onDone(true);

            if (log.isDebugEnabled()) log.debug("Initialized future: " + this);

            sendPartitions();
          } else onDone(exchId.topologyVersion());

          return;
        }

        assert oldestNode.get() != null;

        for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
          if (isCacheAdded(cacheCtx.cacheId(), exchId.topologyVersion())) {
            if (cacheCtx
                .discovery()
                .cacheAffinityNodes(cacheCtx.name(), topologyVersion())
                .isEmpty())
              U.quietAndWarn(log, "No server nodes found for cache client: " + cacheCtx.namex());
          }

          cacheCtx.preloader().onExchangeFutureAdded();
        }

        List<String> cachesWithoutNodes = null;

        if (exchId.isLeft()) {
          for (String name : cctx.cache().cacheNames()) {
            if (cctx.discovery().cacheAffinityNodes(name, topologyVersion()).isEmpty()) {
              if (cachesWithoutNodes == null) cachesWithoutNodes = new ArrayList<>();

              cachesWithoutNodes.add(name);

              // Fire event even if there is no client cache started.
              if (cctx.gridEvents().isRecordable(EventType.EVT_CACHE_NODES_LEFT)) {
                Event evt =
                    new CacheEvent(
                        name,
                        cctx.localNode(),
                        cctx.localNode(),
                        "All server nodes have left the cluster.",
                        EventType.EVT_CACHE_NODES_LEFT,
                        0,
                        false,
                        null,
                        null,
                        null,
                        null,
                        false,
                        null,
                        false,
                        null,
                        null,
                        null);

                cctx.gridEvents().record(evt);
              }
            }
          }
        }

        if (cachesWithoutNodes != null) {
          StringBuilder sb =
              new StringBuilder(
                  "All server nodes for the following caches have left the cluster: ");

          for (int i = 0; i < cachesWithoutNodes.size(); i++) {
            String cache = cachesWithoutNodes.get(i);

            sb.append('\'').append(cache).append('\'');

            if (i != cachesWithoutNodes.size() - 1) sb.append(", ");
          }

          U.quietAndWarn(log, sb.toString());

          U.quietAndWarn(log, "Must have server nodes for caches to operate.");
        }

        assert discoEvt != null;

        assert exchId.nodeId().equals(discoEvt.eventNode().id());

        for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
          GridClientPartitionTopology clientTop =
              cctx.exchange().clearClientTopology(cacheCtx.cacheId());

          long updSeq = clientTop == null ? -1 : clientTop.lastUpdateSequence();

          // Update before waiting for locks.
          if (!cacheCtx.isLocal())
            cacheCtx
                .topology()
                .updateTopologyVersion(exchId, this, updSeq, stopping(cacheCtx.cacheId()));
        }

        // Grab all alive remote nodes with order of equal or less than last joined node.
        rmtNodes =
            new ConcurrentLinkedQueue<>(
                CU.aliveRemoteServerNodesWithCaches(cctx, exchId.topologyVersion()));

        rmtIds = Collections.unmodifiableSet(new HashSet<>(F.nodeIds(rmtNodes)));

        for (Map.Entry<UUID, GridDhtPartitionsSingleMessage> m : singleMsgs.entrySet())
          // If received any messages, process them.
          onReceive(m.getKey(), m.getValue());

        for (Map.Entry<UUID, GridDhtPartitionsFullMessage> m : fullMsgs.entrySet())
          // If received any messages, process them.
          onReceive(m.getKey(), m.getValue());

        AffinityTopologyVersion topVer = exchId.topologyVersion();

        for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
          if (cacheCtx.isLocal()) continue;

          // Must initialize topology after we get discovery event.
          initTopology(cacheCtx);

          cacheCtx.preloader().updateLastExchangeFuture(this);
        }

        IgniteInternalFuture<?> partReleaseFut = cctx.partitionReleaseFuture(topVer);

        // Assign to class variable so it will be included into toString() method.
        this.partReleaseFut = partReleaseFut;

        if (log.isDebugEnabled()) log.debug("Before waiting for partition release future: " + this);

        while (true) {
          try {
            partReleaseFut.get(2 * cctx.gridConfig().getNetworkTimeout(), TimeUnit.MILLISECONDS);

            break;
          } catch (IgniteFutureTimeoutCheckedException ignored) {
            // Print pending transactions and locks that might have led to hang.
            dumpPendingObjects();
          }
        }

        if (log.isDebugEnabled()) log.debug("After waiting for partition release future: " + this);

        if (!F.isEmpty(reqs)) blockGateways();

        if (exchId.isLeft())
          cctx.mvcc().removeExplicitNodeLocks(exchId.nodeId(), exchId.topologyVersion());

        IgniteInternalFuture<?> locksFut = cctx.mvcc().finishLocks(exchId.topologyVersion());

        while (true) {
          try {
            locksFut.get(2 * cctx.gridConfig().getNetworkTimeout(), TimeUnit.MILLISECONDS);

            break;
          } catch (IgniteFutureTimeoutCheckedException ignored) {
            U.warn(
                log,
                "Failed to wait for locks release future. "
                    + "Dumping pending objects that might be the cause: "
                    + cctx.localNodeId());

            U.warn(log, "Locked entries:");

            Map<IgniteTxKey, Collection<GridCacheMvccCandidate>> locks =
                cctx.mvcc().unfinishedLocks(exchId.topologyVersion());

            for (Map.Entry<IgniteTxKey, Collection<GridCacheMvccCandidate>> e : locks.entrySet())
              U.warn(log, "Locked entry [key=" + e.getKey() + ", mvcc=" + e.getValue() + ']');
          }
        }

        for (GridCacheContext cacheCtx : cctx.cacheContexts()) {
          if (cacheCtx.isLocal()) continue;

          // Notify replication manager.
          GridCacheContext drCacheCtx =
              cacheCtx.isNear() ? cacheCtx.near().dht().context() : cacheCtx;

          if (drCacheCtx.isDrEnabled()) drCacheCtx.dr().beforeExchange(topVer, exchId.isLeft());

          // Partition release future is done so we can flush the write-behind store.
          cacheCtx.store().forceFlush();

          // Process queued undeploys prior to sending/spreading map.
          cacheCtx.preloader().unwindUndeploys();

          GridDhtPartitionTopology top = cacheCtx.topology();

          assert topVer.equals(top.topologyVersion())
              : "Topology version is updated only in this class instances inside single ExchangeWorker thread.";

          top.beforeExchange(this);
        }

        for (GridClientPartitionTopology top : cctx.exchange().clientTopologies()) {
          top.updateTopologyVersion(exchId, this, -1, stopping(top.cacheId()));

          top.beforeExchange(this);
        }
      } catch (IgniteInterruptedCheckedException e) {
        onDone(e);

        throw e;
      } catch (Throwable e) {
        U.error(
            log,
            "Failed to reinitialize local partitions (preloading will be stopped): " + exchId,
            e);

        onDone(e);

        if (e instanceof Error) throw (Error) e;

        return;
      }

      if (F.isEmpty(rmtIds)) {
        onDone(exchId.topologyVersion());

        return;
      }

      ready.set(true);

      initFut.onDone(true);

      if (log.isDebugEnabled()) log.debug("Initialized future: " + this);

      // If this node is not oldest.
      if (!oldestNode.get().id().equals(cctx.localNodeId())) sendPartitions();
      else {
        boolean allReceived = allReceived();

        if (allReceived && replied.compareAndSet(false, true)) {
          if (spreadPartitions()) onDone(exchId.topologyVersion());
        }
      }

      scheduleRecheck();
    } else assert false : "Skipped init future: " + this;
  }
  /**
   * @param nodeId Sender node id.
   * @param msg Single partition info.
   */
  public void onReceive(final UUID nodeId, final GridDhtPartitionsSingleMessage msg) {
    assert msg != null;

    assert msg.exchangeId().equals(exchId);

    // Update last seen version.
    while (true) {
      GridCacheVersion old = lastVer.get();

      if (old == null || old.compareTo(msg.lastVersion()) < 0) {
        if (lastVer.compareAndSet(old, msg.lastVersion())) break;
      } else break;
    }

    if (isDone()) {
      if (log.isDebugEnabled())
        log.debug(
            "Received message for finished future (will reply only to sender) [msg="
                + msg
                + ", fut="
                + this
                + ']');

      sendAllPartitions(nodeId, cctx.gridConfig().getNetworkSendRetryCount());
    } else {
      initFut.listen(
          new CI1<IgniteInternalFuture<Boolean>>() {
            @Override
            public void apply(IgniteInternalFuture<Boolean> t) {
              try {
                if (!t.get()) // Just to check if there was an error.
                return;

                ClusterNode loc = cctx.localNode();

                singleMsgs.put(nodeId, msg);

                boolean match = true;

                // Check if oldest node has changed.
                if (!oldestNode.get().equals(loc)) {
                  match = false;

                  synchronized (mux) {
                    // Double check.
                    if (oldestNode.get().equals(loc)) match = true;
                  }
                }

                if (match) {
                  boolean allReceived;

                  synchronized (rcvdIds) {
                    if (rcvdIds.add(nodeId)) updatePartitionSingleMap(msg);

                    allReceived = allReceived();
                  }

                  // If got all replies, and initialization finished, and reply has not been sent
                  // yet.
                  if (allReceived && ready.get() && replied.compareAndSet(false, true)) {
                    spreadPartitions();

                    onDone(exchId.topologyVersion());
                  } else if (log.isDebugEnabled())
                    log.debug(
                        "Exchange future full map is not sent [allReceived="
                            + allReceived()
                            + ", ready="
                            + ready
                            + ", replied="
                            + replied.get()
                            + ", init="
                            + init.get()
                            + ", fut="
                            + this
                            + ']');
                }
              } catch (IgniteCheckedException e) {
                U.error(log, "Failed to initialize exchange future: " + this, e);
              }
            }
          });
    }
  }
 /** Completeness callback. */
 private void onComplete() {
   onDone(tx, err.get());
 }
Пример #11
0
  /**
   * Maps keys to nodes. Note that we can not simply group keys by nodes and send lock request as
   * such approach does not preserve order of lock acquisition. Instead, keys are split in
   * continuous groups belonging to one primary node and locks for these groups are acquired
   * sequentially.
   *
   * @param keys Keys.
   */
  private void map(Iterable<? extends K> keys) {
    try {
      GridDiscoveryTopologySnapshot snapshot = topSnapshot.get();

      assert snapshot != null;

      long topVer = snapshot.topologyVersion();

      assert topVer > 0;

      if (CU.affinityNodes(cctx, topVer).isEmpty()) {
        onDone(
            new GridTopologyException(
                "Failed to map keys for near-only cache (all "
                    + "partition nodes left the grid)."));

        return;
      }

      ConcurrentLinkedDeque8<GridNearLockMapping<K, V>> mappings = new ConcurrentLinkedDeque8<>();

      // Assign keys to primary nodes.
      GridNearLockMapping<K, V> map = null;

      for (K key : keys) {
        GridNearLockMapping<K, V> updated = map(key, map, topVer);

        // If new mapping was created, add to collection.
        if (updated != map) mappings.add(updated);

        map = updated;
      }

      if (isDone()) {
        if (log.isDebugEnabled()) log.debug("Abandoning (re)map because future is done: " + this);

        return;
      }

      if (log.isDebugEnabled())
        log.debug("Starting (re)map for mappings [mappings=" + mappings + ", fut=" + this + ']');

      // Create mini futures.
      for (Iterator<GridNearLockMapping<K, V>> iter = mappings.iterator(); iter.hasNext(); ) {
        GridNearLockMapping<K, V> mapping = iter.next();

        GridNode node = mapping.node();
        Collection<K> mappedKeys = mapping.mappedKeys();

        assert !mappedKeys.isEmpty();

        GridNearLockRequest<K, V> req = null;

        Collection<K> distributedKeys = new ArrayList<>(mappedKeys.size());

        boolean explicit = false;

        for (K key : mappedKeys) {
          while (true) {
            GridNearCacheEntry<K, V> entry = null;

            try {
              entry = cctx.near().entryExx(key, topVer);

              if (!cctx.isAll(entry.wrap(false), filter)) {
                if (log.isDebugEnabled())
                  log.debug("Entry being locked did not pass filter (will not lock): " + entry);

                onComplete(false, false);

                return;
              }

              // Removed exception may be thrown here.
              GridCacheMvccCandidate<K> cand = addEntry(topVer, entry, node.id());

              if (isDone()) {
                if (log.isDebugEnabled())
                  log.debug(
                      "Abandoning (re)map because future is done after addEntry attempt "
                          + "[fut="
                          + this
                          + ", entry="
                          + entry
                          + ']');

                return;
              }

              if (cand != null) {
                if (tx == null && !cand.reentry())
                  cctx.mvcc().addExplicitLock(threadId, cand, snapshot);

                GridTuple3<GridCacheVersion, V, byte[]> val = entry.versionedValue();

                if (val == null) {
                  GridDhtCacheEntry<K, V> dhtEntry = dht().peekExx(key);

                  try {
                    if (dhtEntry != null) val = dhtEntry.versionedValue(topVer);
                  } catch (GridCacheEntryRemovedException ignored) {
                    assert dhtEntry.obsolete()
                        : " Got removed exception for non-obsolete entry: " + dhtEntry;

                    if (log.isDebugEnabled())
                      log.debug(
                          "Got removed exception for DHT entry in map (will ignore): " + dhtEntry);
                  }
                }

                GridCacheVersion dhtVer = null;

                if (val != null) {
                  dhtVer = val.get1();

                  valMap.put(key, val);
                }

                if (!cand.reentry()) {
                  if (req == null) {
                    req =
                        new GridNearLockRequest<>(
                            topVer,
                            cctx.nodeId(),
                            threadId,
                            futId,
                            lockVer,
                            inTx(),
                            implicitTx(),
                            implicitSingleTx(),
                            read,
                            isolation(),
                            isInvalidate(),
                            timeout,
                            syncCommit(),
                            syncRollback(),
                            mappedKeys.size(),
                            inTx() ? tx.size() : mappedKeys.size(),
                            inTx() ? tx.groupLockKey() : null,
                            inTx() && tx.partitionLock(),
                            inTx() ? tx.subjectId() : null);

                    mapping.request(req);
                  }

                  distributedKeys.add(key);

                  GridCacheTxEntry<K, V> writeEntry = tx != null ? tx.writeMap().get(key) : null;

                  if (tx != null) tx.addKeyMapping(key, mapping.node());

                  req.addKeyBytes(
                      key,
                      node.isLocal() ? null : entry.getOrMarshalKeyBytes(),
                      retval && dhtVer == null,
                      dhtVer, // Include DHT version to match remote DHT entry.
                      writeEntry,
                      inTx() ? tx.entry(key).drVersion() : null,
                      cctx);

                  // Clear transfer required flag since we are sending message.
                  if (writeEntry != null) writeEntry.transferRequired(false);
                }

                if (cand.reentry())
                  explicit = tx != null && !entry.hasLockCandidate(tx.xidVersion());
              } else
                // Ignore reentries within transactions.
                explicit = tx != null && !entry.hasLockCandidate(tx.xidVersion());

              if (explicit) tx.addKeyMapping(key, mapping.node());

              break;
            } catch (GridCacheEntryRemovedException ignored) {
              assert entry.obsolete() : "Got removed exception on non-obsolete entry: " + entry;

              if (log.isDebugEnabled())
                log.debug("Got removed entry in lockAsync(..) method (will retry): " + entry);
            }
          }

          // Mark mapping explicit lock flag.
          if (explicit) {
            boolean marked = tx != null && tx.markExplicit(node.id());

            assert tx == null || marked;
          }
        }

        if (!distributedKeys.isEmpty()) mapping.distributedKeys(distributedKeys);
        else {
          assert mapping.request() == null;

          iter.remove();
        }
      }

      cctx.mvcc().recheckPendingLocks();

      proceedMapping(mappings);
    } catch (GridException ex) {
      onError(ex);
    }
  }
 /**
  * Get underlying collection.
  *
  * @return Collection.
  */
 @SuppressWarnings("ConstantConditions")
 protected Collection<T> collection() {
   return ref.get().get1();
 }
  /** Checks window consistency. Used for testing. */
  void consistencyCheck() {
    WindowHolder win = ref.get();

    consistencyCheck(win.collection(), win.set(), win.size());
  }
  /** @param evt Event to add. */
  private void add(E evt) {
    WindowHolder tup = ref.get();

    if (addInternal(evt, tup.collection(), tup.set())) tup.size().incrementAndGet();
  }
  /** {@inheritDoc} */
  @Override
  protected GridStreamerWindowIterator<E> iterator0() {
    WindowHolder win = ref.get();

    return iteratorInternal(win.collection(), win.set(), win.size());
  }
  /** {@inheritDoc} */
  @Override
  public int size() {
    int size = ref.get().size().get();

    return size > 0 ? size : 0;
  }