/** 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();
    }
  }
  /**
   * @param nodeId Sender node ID.
   * @param msg Response to prepare request.
   */
  private void processPrepareResponse(UUID nodeId, GridDistributedTxPrepareResponse<K, V> msg) {
    assert nodeId != null;
    assert msg != null;

    GridReplicatedTxLocal<K, V> tx = ctx.tm().tx(msg.version());

    if (tx == null) {
      if (log.isDebugEnabled())
        log.debug(
            "Received prepare response for non-existing transaction [senderNodeId="
                + nodeId
                + ", res="
                + msg
                + ']');

      return;
    }

    GridReplicatedTxPrepareFuture<K, V> future = (GridReplicatedTxPrepareFuture<K, V>) tx.future();

    if (future != null) future.onResult(nodeId, msg);
    else
      U.error(
          log,
          "Received prepare response for transaction with no future [res="
              + msg
              + ", tx="
              + tx
              + ']');
  }
  /**
   * Processes unlock request.
   *
   * @param nodeId Sender node ID.
   * @param req Unlock request.
   */
  @SuppressWarnings({"unchecked"})
  private void processUnlockRequest(UUID nodeId, GridDistributedUnlockRequest req) {
    assert nodeId != null;

    try {
      ClassLoader ldr = ctx.deploy().globalLoader();
      List<byte[]> keys = req.keyBytes();

      for (byte[] keyBytes : keys) {
        K key = (K) U.unmarshal(ctx.marshaller(), new ByteArrayInputStream(keyBytes), ldr);

        while (true) {
          boolean created = false;

          GridDistributedCacheEntry<K, V> entry = peekexx(key);

          if (entry == null) {
            entry = entryexx(key);

            created = true;
          }

          try {
            entry.doneRemote(
                req.version(), req.version(), req.committedVersions(), req.rolledbackVersions());

            // Note that we don't reorder completed versions here,
            // as there is no point to reorder relative to the version
            // we are about to remove.
            if (entry.removeLock(req.version())) {
              if (log.isDebugEnabled())
                log.debug("Removed lock [lockId=" + req.version() + ", key=" + key + ']');

              if (created && entry.markObsolete(req.version())) removeIfObsolete(entry.key());
            } else if (log.isDebugEnabled())
              log.debug(
                  "Received unlock request for unknown candidate "
                      + "(added to cancelled locks set): "
                      + req);

            break;
          } catch (GridCacheEntryRemovedException ignored) {
            if (log.isDebugEnabled())
              log.debug(
                  "Received remove lock request for removed entry (will retry) [entry="
                      + entry
                      + ", req="
                      + req
                      + ']');
          }
        }
      }
    } catch (GridException e) {
      U.error(log, "Failed to unmarshal unlock key (unlock will not be performed): " + req, e);
    }
  }
  /**
   * 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;

    Collection<GridRichNode> nodes = ctx.remoteNodes(keys);

    try {
      // Send request to remove from remote nodes.
      GridDistributedUnlockRequest<K, V> req = new GridDistributedUnlockRequest<K, V>(keys.size());

      req.version(ver);

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

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

              if (cand != null) {
                // Remove candidate from local node first.
                if (entry.removeLock(cand.version())) {
                  // If there is only local node in this lock's topology,
                  // then there is no reason to distribute the request.
                  if (nodes.isEmpty()) 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 (nodes.isEmpty()) return;

      req.completedVersions(ctx.tm().committedVersions(ver), ctx.tm().rolledbackVersions(ver));

      if (!req.keyBytes().isEmpty())
        // We don't wait for reply to this message.
        ctx.io().safeSend(nodes, req, null);
    } catch (GridException ex) {
      U.error(log, "Failed to unlock the lock for keys: " + keys, ex);
    }
  }
Example #5
0
  /**
   * Notifies single listener.
   *
   * @param lsnr Listener.
   */
  private void notifyListener(GridInClosure<? super GridFuture<R>> lsnr) {
    assert lsnr != null;

    try {
      lsnr.apply(this);
    } catch (IllegalStateException ignore) {
      U.warn(
          null,
          "Failed to notify listener (grid is stopped) [grid="
              + ctx.gridName()
              + ", lsnr="
              + lsnr
              + ']');
    } catch (RuntimeException e) {
      U.error(log, "Failed to notify listener: " + lsnr, e);

      throw e;
    } catch (Error e) {
      U.error(log, "Failed to notify listener: " + lsnr, e);

      throw e;
    }
  }
  /** @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);
    }
  }
  /** {@inheritDoc} */
  @SuppressWarnings({"unchecked"})
  @Override
  public void unlockAll(
      Collection<? extends K> keys, GridPredicate<? super GridCacheEntry<K, V>>[] filter) {
    if (keys == null || keys.isEmpty()) return;

    Collection<? extends GridNode> nodes = ctx.remoteNodes(keys);

    try {
      GridDistributedUnlockRequest<K, V> req = new GridDistributedUnlockRequest<K, V>(keys.size());

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

        if (!ctx.isAll(entry.wrap(false), filter)) continue;

        // Unlock local lock first.
        GridCacheMvccCandidate<K> rmv = entry.removeLock();

        if (rmv != null && !nodes.isEmpty()) {
          if (!rmv.reentry()) {
            req.addKey(entry.key(), entry.getOrMarshalKeyBytes(), ctx);

            // We are assuming that lock ID is the same for all keys.
            req.version(rmv.version());

            if (log.isDebugEnabled()) log.debug("Removed lock (will distribute): " + rmv);
          } else {
            if (log.isDebugEnabled())
              log.debug(
                  "Locally unlocked lock reentry without distributing to other nodes [removed="
                      + rmv
                      + ", entry="
                      + entry
                      + ']');
          }
        } else {
          if (log.isDebugEnabled())
            log.debug(
                "Current thread still owns lock (or there are no other nodes) [lock="
                    + rmv
                    + ", curThreadId="
                    + Thread.currentThread().getId()
                    + ']');
        }
      }

      // Don't proceed of no keys to unlock.
      if (req.keyBytes().isEmpty()) {
        if (log.isDebugEnabled())
          log.debug("No keys to unlock locally (was it reentry unlock?): " + keys);

        return;
      }

      // We don't wait for reply to this message. Receiving side will have
      // to make sure that unlock requests don't come before lock requests.
      ctx.io().safeSend(nodes, req, null);
    } catch (GridException e) {
      U.error(log, "Failed to unlock keys: " + keys, e);
    }
  }
  /** {@inheritDoc} */
  @SuppressWarnings({"unchecked", "ThrowableInstanceNeverThrown"})
  @Override
  protected GridFuture<Boolean> lockAllAsync(
      Collection<? extends K> keys,
      long timeout,
      GridCacheTxLocalEx<K, V> tx,
      boolean isInvalidate,
      boolean isRead,
      boolean retval,
      GridCacheTxIsolation isolation,
      GridPredicate<? super GridCacheEntry<K, V>>[] filter) {
    if (keys.isEmpty()) return new GridFinishedFuture<Boolean>(ctx.kernalContext(), true);

    Collection<GridRichNode> nodes = ctx.remoteNodes(keys);

    final GridReplicatedLockFuture<K, V> fut =
        new GridReplicatedLockFuture<K, V>(ctx, keys, tx, this, nodes, timeout, filter);

    GridDistributedLockRequest<K, V> req =
        new GridDistributedLockRequest<K, V>(
            locNodeId,
            Thread.currentThread().getId(),
            fut.futureId(),
            fut.version(),
            tx != null,
            isRead,
            isolation,
            isInvalidate,
            timeout,
            keys.size());

    try {
      // Must add future before redying locks.
      if (!ctx.mvcc().addFuture(fut))
        throw new IllegalStateException("Duplicate future ID: " + fut);

      boolean distribute = false;

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

          try {
            entry = entryexx(key);

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

              fut.onDone(false);

              return fut;
            }

            // Removed exception may be thrown here.
            GridCacheMvccCandidate<K> cand = fut.addEntry(entry);

            if (cand != null) {
              req.addKeyBytes(
                  key,
                  cand.reentry() ? null : entry.getOrMarshalKeyBytes(),
                  retval,
                  entry.localCandidates(fut.version()),
                  ctx);

              req.completedVersions(
                  ctx.tm().committedVersions(fut.version()),
                  ctx.tm().rolledbackVersions(fut.version()));

              distribute = !cand.reentry();
            } else if (fut.isDone()) return fut;

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

      // If nothing to distribute at this point,
      // then all locks are reentries.
      if (!distribute) fut.complete(true);

      if (nodes.isEmpty()) fut.readyLocks();

      // No reason to send request if all locks are locally re-entered,
      // or if timeout is negative and local locks could not be acquired.
      if (fut.isDone()) return fut;

      try {
        ctx.io()
            .safeSend(
                fut.nodes(),
                req,
                new P1<GridNode>() {
                  @Override
                  public boolean apply(GridNode node) {
                    fut.onNodeLeft(node.id());

                    return !fut.isDone();
                  }
                });
      } catch (GridException e) {
        U.error(
            log,
            "Failed to send lock request to node [nodes="
                + U.toShortString(nodes)
                + ", req="
                + req
                + ']',
            e);

        fut.onError(e);
      }

      return fut;
    } catch (GridException e) {
      Throwable err = new GridException("Failed to acquire asynchronous lock for keys: " + keys, e);

      // Clean-up.
      fut.onError(err);

      ctx.mvcc().removeFuture(fut);

      return fut;
    }
  }
  /**
   * @param nodeId Sender node ID.
   * @param req Finish transaction message.
   */
  @SuppressWarnings({"CatchGenericClass"})
  private void processFinishRequest(UUID nodeId, GridDistributedTxFinishRequest<K, V> req) {
    assert nodeId != null;
    assert req != null;

    GridReplicatedTxRemote<K, V> tx = ctx.tm().tx(req.version());

    try {
      ClassLoader ldr = ctx.deploy().globalLoader();

      if (req.commit()) {
        // If lock was acquired explicitly.
        if (tx == null) {
          // Create transaction and add entries.
          tx =
              ctx.tm()
                  .onCreated(
                      new GridReplicatedTxRemote<K, V>(
                          ldr,
                          nodeId,
                          req.threadId(),
                          req.version(),
                          req.commitVersion(),
                          PESSIMISTIC,
                          READ_COMMITTED,
                          req.isInvalidate(),
                          /*timeout */ 0,
                          /*read entries*/ null,
                          req.writes(),
                          ctx));

          if (tx == null || !ctx.tm().onStarted(tx))
            throw new GridCacheTxRollbackException(
                "Attempt to start a completed " + "transaction: " + req);
        } else {
          boolean set = tx.commitVersion(req.commitVersion());

          assert set;
        }

        Collection<GridCacheTxEntry<K, V>> writeEntries = req.writes();

        if (!F.isEmpty(writeEntries)) {
          // In OPTIMISTIC mode, we get the values at PREPARE stage.
          assert tx.concurrency() == PESSIMISTIC;

          for (GridCacheTxEntry<K, V> entry : writeEntries) {
            // Unmarshal write entries.
            entry.unmarshal(ctx, ldr);

            if (log.isDebugEnabled())
              log.debug(
                  "Unmarshalled transaction entry from pessimistic transaction [key="
                      + entry.key()
                      + ", value="
                      + entry.value()
                      + ", tx="
                      + tx
                      + ']');

            if (!tx.setWriteValue(entry))
              U.warn(
                  log,
                  "Received entry to commit that was not present in transaction [entry="
                      + entry
                      + ", tx="
                      + tx
                      + ']');
          }
        }

        // Add completed versions.
        tx.doneRemote(req.baseVersion(), req.committedVersions(), req.rolledbackVersions());

        if (tx.pessimistic()) tx.prepare();

        tx.commit();
      } else if (tx != null) {
        tx.doneRemote(req.baseVersion(), req.committedVersions(), req.rolledbackVersions());

        tx.rollback();
      }

      if (req.replyRequired()) {
        GridCacheMessage<K, V> res =
            new GridDistributedTxFinishResponse<K, V>(req.version(), req.futureId());

        try {
          ctx.io().send(nodeId, res);
        } catch (Throwable e) {
          // Double-check.
          if (ctx.discovery().node(nodeId) == null) {
            if (log.isDebugEnabled())
              log.debug(
                  "Node left while sending finish response [nodeId="
                      + nodeId
                      + ", res="
                      + res
                      + ']');
          } else
            U.error(
                log,
                "Failed to send finish response to node [nodeId=" + nodeId + ", res=" + res + ']',
                e);
        }
      }
    } catch (GridCacheTxRollbackException e) {
      if (log.isDebugEnabled())
        log.debug("Attempted to start a completed transaction (will ignore): " + e);
    } catch (Throwable e) {
      U.error(
          log,
          "Failed completing transaction [commit=" + req.commit() + ", tx=" + CU.txString(tx) + ']',
          e);

      if (tx != null) tx.rollback();
    }
  }
  /**
   * Removes obsolete deployments in case of redeploy.
   *
   * @param meta Request metadata.
   * @return List of shares deployment.
   */
  private GridTuple2<Boolean, SharedDeployment> checkRedeploy(GridDeploymentMetadata meta) {
    assert Thread.holdsLock(mux);

    SharedDeployment newDep = null;

    for (List<SharedDeployment> deps : cache.values()) {
      for (SharedDeployment dep : deps) {
        if (!dep.isUndeployed() && !dep.isPendingUndeploy()) {
          long undeployTimeout = ctx.config().getNetworkTimeout();

          SharedDeployment doomed = null;

          // Only check deployments with no participants.
          if (!dep.hasParticipants()) {
            // In case of SHARED deployment it is possible to get hear if
            // unmarshalling happens during undeploy. In this case, we
            // simply don't do anything.
            if (dep.deployMode() == CONTINUOUS) {
              if (dep.existingDeployedClass(meta.className()) != null) {
                // Change from shared deploy to shared undeploy or user version change.
                // Simply remove all deployments with no participating nodes.
                if (meta.deploymentMode() == SHARED
                    || !meta.userVersion().equals(dep.userVersion())) doomed = dep;
              }
            }
          }
          // If there are participants, we undeploy if class loader ID on some node changed.
          else if (dep.existingDeployedClass(meta.className()) != null) {
            GridTuple2<GridUuid, Long> ldr = dep.getClassLoaderId(meta.senderNodeId());

            if (ldr != null) {
              if (!ldr.get1().equals(meta.classLoaderId())) {
                // If deployed sequence number is less, then schedule for undeployment.
                if (ldr.get2() < meta.sequenceNumber()) {
                  if (log.isDebugEnabled())
                    log.debug(
                        "Received request for a class with newer sequence number "
                            + "(will schedule current class for undeployment) [newSeq="
                            + meta.sequenceNumber()
                            + ", oldSeq="
                            + ldr.get2()
                            + ", senderNodeId="
                            + meta.senderNodeId()
                            + ", newClsLdrId="
                            + meta.classLoaderId()
                            + ", oldClsLdrId="
                            + ldr.get1()
                            + ']');

                  doomed = dep;
                } else if (ldr.get2() > meta.sequenceNumber()) {
                  long time = System.currentTimeMillis() - dep.timestamp();

                  if (newDep == null && time < ctx.config().getNetworkTimeout()) {
                    // Set undeployTimeout, so the class will be scheduled
                    // for undeployment.
                    undeployTimeout = ctx.config().getNetworkTimeout() - time;

                    if (log.isDebugEnabled())
                      log.debug(
                          "Received execution request for a stale class (will deploy and "
                              + "schedule undeployment in "
                              + undeployTimeout
                              + "ms) "
                              + "[curSeq="
                              + ldr.get2()
                              + ", staleSeq="
                              + meta.sequenceNumber()
                              + ", cls="
                              + meta.className()
                              + ", senderNodeId="
                              + meta.senderNodeId()
                              + ", curLdrId="
                              + ldr.get1()
                              + ", staleLdrId="
                              + meta.classLoaderId()
                              + ']');

                    // We got the redeployed class before the old one.
                    // Simply create a temporary deployment for the sender node,
                    // and schedule undeploy for it.
                    newDep = createNewDeployment(meta, false);

                    doomed = newDep;
                  } else {
                    U.warn(
                        log,
                        "Received execution request for a class that has been redeployed "
                            + "(will ignore): "
                            + meta.alias());

                    if (log.isDebugEnabled())
                      log.debug(
                          "Received execution request for a class that has been redeployed "
                              + "(will ignore) [alias="
                              + meta.alias()
                              + ", dep="
                              + dep
                              + ']');

                    return F.t(false, null);
                  }
                } else {
                  U.error(
                      log,
                      "Sequence number does not correspond to class loader ID [seqNum="
                          + meta.sequenceNumber()
                          + ", dep="
                          + dep
                          + ']');

                  return F.t(false, null);
                }
              }
            }
          }

          if (doomed != null) {
            doomed.onUndeployScheduled();

            if (log.isDebugEnabled()) log.debug("Deployment was scheduled for undeploy: " + doomed);

            // Lifespan time.
            final long endTime = System.currentTimeMillis() + undeployTimeout;

            // Deployment to undeploy.
            final SharedDeployment undep = doomed;

            ctx.timeout()
                .addTimeoutObject(
                    new GridTimeoutObject() {
                      @Override
                      public GridUuid timeoutId() {
                        return undep.classLoaderId();
                      }

                      @Override
                      public long endTime() {
                        return endTime < 0 ? Long.MAX_VALUE : endTime;
                      }

                      @Override
                      public void onTimeout() {
                        boolean removed = false;

                        // Hot redeployment.
                        synchronized (mux) {
                          assert undep.isPendingUndeploy();

                          if (!undep.isUndeployed()) {
                            undep.undeploy();

                            undep.onRemoved();

                            removed = true;

                            Collection<SharedDeployment> deps = cache.get(undep.userVersion());

                            if (deps != null) {
                              for (Iterator<SharedDeployment> i = deps.iterator(); i.hasNext(); )
                                if (i.next() == undep) i.remove();

                              if (deps.isEmpty()) cache.remove(undep.userVersion());
                            }

                            if (log.isInfoEnabled())
                              log.info(
                                  "Undeployed class loader due to deployment mode change, "
                                      + "user version change, or hot redeployment: "
                                      + undep);
                          }
                        }

                        // Outside synchronization.
                        if (removed) undep.recordUndeployed(null);
                      }
                    });
          }
        }
      }
    }

    if (newDep != null) {
      List<SharedDeployment> list =
          F.addIfAbsent(cache, meta.userVersion(), F.<SharedDeployment>newList());

      assert list != null;

      list.add(newDep);
    }

    return F.t(true, newDep);
  }
  /**
   * Processes lock request.
   *
   * @param nodeId Sender node ID.
   * @param msg Lock request.
   */
  @SuppressWarnings({"unchecked", "ThrowableInstanceNeverThrown"})
  private void processLockRequest(UUID nodeId, GridDistributedLockRequest<K, V> msg) {
    assert !nodeId.equals(locNodeId);

    List<byte[]> keys = msg.keyBytes();

    int cnt = keys.size();

    GridReplicatedTxRemote<K, V> tx = null;

    GridDistributedLockResponse res;

    ClassLoader ldr = null;

    try {
      ldr = ctx.deploy().globalLoader();

      if (ldr != null) {
        res = new GridDistributedLockResponse(msg.version(), msg.futureId(), cnt);

        for (int i = 0; i < keys.size(); i++) {
          byte[] bytes = keys.get(i);
          K key = msg.keys().get(i);

          Collection<GridCacheMvccCandidate<K>> cands = msg.candidatesByIndex(i);

          if (bytes == null) continue;

          if (log.isDebugEnabled()) log.debug("Unmarshalled key: " + key);

          GridDistributedCacheEntry<K, V> entry = null;

          while (true) {
            try {
              entry = entryexx(key);

              // Handle implicit locks for pessimistic transactions.
              if (msg.inTx()) {
                tx = ctx.tm().tx(msg.version());

                if (tx != null) {
                  if (msg.txRead()) tx.addRead(key, bytes);
                  else tx.addWrite(key, bytes);
                } else {
                  tx =
                      new GridReplicatedTxRemote<K, V>(
                          nodeId,
                          msg.threadId(),
                          msg.version(),
                          null,
                          PESSIMISTIC,
                          msg.isolation(),
                          msg.isInvalidate(),
                          msg.timeout(),
                          key,
                          bytes,
                          msg.txRead(),
                          ctx);

                  tx = ctx.tm().onCreated(tx);

                  if (tx == null || !ctx.tm().onStarted(tx))
                    throw new GridCacheTxRollbackException(
                        "Failed to acquire lock "
                            + "(transaction has been completed): "
                            + msg.version());
                }
              }

              // Add remote candidate before reordering.
              entry.addRemote(
                  msg.nodeId(),
                  null,
                  msg.threadId(),
                  msg.version(),
                  msg.timeout(),
                  tx != null && tx.ec(),
                  tx != null,
                  tx != null && tx.implicitSingle());

              // Remote candidates for ordered lock queuing.
              entry.addRemoteCandidates(
                  cands, msg.version(), msg.committedVersions(), msg.rolledbackVersions());

              // Double-check in case if sender node left the grid.
              if (ctx.discovery().node(msg.nodeId()) == null) {
                if (log.isDebugEnabled())
                  log.debug(
                      "Node requesting lock left grid (lock request will be ignored): " + msg);

                if (tx != null) tx.rollback();

                return;
              }

              res.setCandidates(
                  i,
                  entry.localCandidates(),
                  ctx.tm().committedVersions(msg.version()),
                  ctx.tm().rolledbackVersions(msg.version()));

              res.addValueBytes(
                  entry.rawGet(), msg.returnValue(i) ? entry.valueBytes(null) : null, ctx);

              // Entry is legit.
              break;
            } catch (GridCacheEntryRemovedException ignored) {
              assert entry.obsoleteVersion() != null
                  : "Obsolete flag not set on removed entry: " + entry;

              if (log.isDebugEnabled())
                log.debug(
                    "Received entry removed exception (will retry on renewed entry): " + entry);

              if (tx != null) {
                tx.clearEntry(entry.key());

                if (log.isDebugEnabled())
                  log.debug(
                      "Cleared removed entry from remote transaction (will retry) [entry="
                          + entry
                          + ", tx="
                          + tx
                          + ']');
              }
            }
          }
        }
      } else {
        String err = "Failed to acquire deployment class for message: " + msg;

        U.warn(log, err);

        res =
            new GridDistributedLockResponse(msg.version(), msg.futureId(), new GridException(err));
      }
    } catch (GridCacheTxRollbackException e) {
      if (log.isDebugEnabled())
        log.debug("Received lock request for completed transaction (will ignore): " + e);

      res = new GridDistributedLockResponse(msg.version(), msg.futureId(), e);
    } catch (GridException e) {
      String err = "Failed to unmarshal at least one of the keys for lock request message: " + msg;

      log.error(err, e);

      res =
          new GridDistributedLockResponse(msg.version(), msg.futureId(), new GridException(err, e));

      if (tx != null) tx.rollback();
    } catch (GridDistributedLockCancelledException ignored) {
      // Received lock request for cancelled lock.
      if (log.isDebugEnabled())
        log.debug("Received lock request for canceled lock (will ignore): " + msg);

      if (tx != null) tx.rollback();

      // Don't send response back.
      return;
    }

    GridNode node = ctx.discovery().node(msg.nodeId());

    boolean releaseAll = false;

    if (node != null) {
      try {
        // Reply back to sender.
        ctx.io().send(node, res);
      } catch (GridException e) {
        U.error(log, "Failed to send message to node (did the node leave grid?): " + node.id(), e);

        releaseAll = ldr != null;
      }
    }
    // If sender left grid, release all locks acquired so far.
    else releaseAll = ldr != null;

    // Release all locks because sender node left grid.
    if (releaseAll) {
      for (K key : msg.keys()) {
        while (true) {
          GridDistributedCacheEntry<K, V> entry = peekexx(key);

          try {
            if (entry != null) entry.removeExplicitNodeLocks(msg.nodeId());

            break;
          } catch (GridCacheEntryRemovedException ignore) {
            if (log.isDebugEnabled())
              log.debug(
                  "Attempted to remove lock on removed entity during failure "
                      + "of replicated lock request handling (will retry): "
                      + entry);
          }
        }
      }

      U.warn(
          log, "Sender node left grid in the midst of lock acquisition (locks will be released).");
    }
  }
  /**
   * @param depMode Deployment mode.
   * @param ldr Class loader to deploy.
   * @param cls Class.
   * @param alias Class alias.
   * @return Deployment.
   */
  @SuppressWarnings({"ConstantConditions"})
  private GridDeployment deploy(
      GridDeploymentMode depMode, ClassLoader ldr, Class<?> cls, String alias) {
    assert Thread.holdsLock(mux);

    LinkedList<GridDeployment> cachedDeps = null;

    GridDeployment dep = null;

    // Find existing class loader info.
    for (LinkedList<GridDeployment> deps : cache.values()) {
      for (GridDeployment d : deps) {
        if (d.classLoader() == ldr) {
          // Cache class and alias.
          d.addDeployedClass(cls, alias);

          cachedDeps = deps;

          dep = d;

          break;
        }
      }

      if (cachedDeps != null) {
        break;
      }
    }

    if (cachedDeps != null) {
      assert dep != null;

      cache.put(alias, cachedDeps);

      if (!cls.getName().equals(alias)) {
        // Cache by class name as well.
        cache.put(cls.getName(), cachedDeps);
      }

      return dep;
    }

    GridUuid ldrId = GridUuid.randomUuid();

    long seqNum = seq.incrementAndGet();

    String userVer = getUserVersion(ldr);

    dep = new GridDeployment(depMode, ldr, ldrId, seqNum, userVer, cls.getName(), true);

    dep.addDeployedClass(cls, alias);

    LinkedList<GridDeployment> deps =
        F.addIfAbsent(cache, alias, F.<GridDeployment>newLinkedList());

    if (!deps.isEmpty()) {
      for (GridDeployment d : deps) {
        if (!d.isUndeployed()) {
          U.error(
              log,
              "Found more than one active deployment for the same resource "
                  + "[cls="
                  + cls
                  + ", depMode="
                  + depMode
                  + ", dep="
                  + d
                  + ']');

          return null;
        }
      }
    }

    // Add at the beginning of the list for future fast access.
    deps.addFirst(dep);

    if (!cls.getName().equals(alias)) {
      // Cache by class name as well.
      cache.put(cls.getName(), deps);
    }

    if (log.isDebugEnabled()) {
      log.debug("Created new deployment: " + dep);
    }

    return dep;
  }
  /** {@inheritDoc} */
  @Nullable
  @SuppressWarnings({"UnusedCatchParameter"})
  @Override
  public GridDeployment getDeployment(GridDeploymentMetadata meta) {
    GridDeployment dep;

    Class<?> cls = null;

    String alias = meta.alias();

    synchronized (mux) {
      // Validate metadata.
      assert meta.alias() != null;

      dep = getDeployment(meta.alias());

      if (dep != null) {
        if (log.isDebugEnabled()) {
          log.debug("Acquired deployment class from local cache: " + dep);
        }

        return dep;
      }

      GridDeploymentResource rsrc = spi.findResource(meta.alias());

      if (rsrc != null) {
        dep =
            deploy(
                ctx.config().getDeploymentMode(),
                rsrc.getClassLoader(),
                rsrc.getResourceClass(),
                alias);

        if (dep == null) {
          return null;
        }

        if (log.isDebugEnabled()) {
          log.debug("Acquired deployment class from SPI: " + dep);
        }
      }
      // Auto-deploy.
      else {
        ClassLoader ldr = meta.classLoader();

        if (ldr == null) {
          ldr = Thread.currentThread().getContextClassLoader();

          // Safety.
          if (ldr == null) {
            ldr = ctxLdr;
          }
        }

        // Don't auto-deploy locally in case of nested execution.
        if (ldr instanceof GridDeploymentClassLoader) {
          return null;
        }

        try {
          // Check that class can be loaded.
          cls = ldr.loadClass(meta.alias());

          spi.register(ldr, cls);

          rsrc = spi.findResource(alias);

          if (rsrc != null && rsrc.getResourceClass().equals(cls)) {
            if (log.isDebugEnabled()) {
              log.debug("Retrieved auto-loaded resource from spi: " + rsrc);
            }

            dep = deploy(ctx.config().getDeploymentMode(), ldr, cls, alias);

            if (dep == null) {
              return null;
            }
          } else {
            U.warn(
                log,
                "Failed to find resource from deployment SPI even after registering it: "
                    + meta.alias());

            return null;
          }
        } catch (ClassNotFoundException e) {
          if (log.isDebugEnabled()) {
            log.debug(
                "Failed to load class for local auto-deployment [ldr="
                    + ldr
                    + ", meta="
                    + meta
                    + ']');
          }

          return null;
        } catch (GridSpiException e) {
          U.error(log, "Failed to deploy local class: " + meta.alias(), e);

          return null;
        }
      }
    }

    if (cls != null) {
      recordDeploy(cls, alias, meta.isRecord());

      dep.addDeployedClass(cls, meta.className(), meta.alias());
    }

    if (log.isDebugEnabled()) {
      log.debug("Acquired deployment class: " + dep);
    }

    return dep;
  }
  /**
   * @param nodeId Sender node ID.
   * @param msg Prepare request.
   */
  @SuppressWarnings({"InstanceofCatchParameter"})
  private void processPrepareRequest(UUID nodeId, GridDistributedTxPrepareRequest<K, V> msg) {
    assert nodeId != null;
    assert msg != null;

    GridReplicatedTxRemote<K, V> tx = null;

    GridDistributedTxPrepareResponse<K, V> res;

    try {
      tx =
          new GridReplicatedTxRemote<K, V>(
              ctx.deploy().globalLoader(),
              nodeId,
              msg.threadId(),
              msg.version(),
              msg.commitVersion(),
              msg.concurrency(),
              msg.isolation(),
              msg.isInvalidate(),
              msg.timeout(),
              msg.reads(),
              msg.writes(),
              ctx);

      tx = ctx.tm().onCreated(tx);

      if (tx == null || !ctx.tm().onStarted(tx))
        throw new GridCacheTxRollbackException("Attempt to start a completed transaction: " + tx);

      // Prepare prior to reordering, so the pending locks added
      // in prepare phase will get properly ordered as well.
      tx.prepare();

      // Add remote candidates and reorder completed and uncompleted versions.
      tx.addRemoteCandidates(
          msg.candidatesByKey(), msg.committedVersions(), msg.rolledbackVersions());

      if (msg.concurrency() == EVENTUALLY_CONSISTENT) {
        if (log.isDebugEnabled()) log.debug("Committing transaction during remote prepare: " + tx);

        tx.commit();

        if (log.isDebugEnabled()) log.debug("Committed transaction during remote prepare: " + tx);

        // Don't send response.
        return;
      }

      res = new GridDistributedTxPrepareResponse<K, V>(msg.version());

      Map<K, Collection<GridCacheMvccCandidate<K>>> cands = tx.localCandidates();

      // Add local candidates (completed version must be set below).
      res.candidates(cands);
    } catch (GridException e) {
      if (e instanceof GridCacheTxRollbackException) {
        if (log.isDebugEnabled())
          log.debug("Transaction was rolled back before prepare completed: " + tx);
      } else if (e instanceof GridCacheTxOptimisticException) {
        if (log.isDebugEnabled())
          log.debug("Optimistic failure for remote transaction (will rollback): " + tx);
      } else {
        U.error(log, "Failed to process prepare request: " + msg, e);
      }

      if (tx != null)
        // Automatically rollback remote transactions.
        tx.rollback();

      // Don't send response.
      if (msg.concurrency() == EVENTUALLY_CONSISTENT) return;

      res = new GridDistributedTxPrepareResponse<K, V>(msg.version());

      res.error(e);
    }

    // Add completed versions.
    res.completedVersions(
        ctx.tm().committedVersions(msg.version()), ctx.tm().rolledbackVersions(msg.version()));

    assert msg.concurrency() != EVENTUALLY_CONSISTENT;

    GridNode node = ctx.discovery().node(nodeId);

    if (node != null) {
      try {
        // Reply back to sender.
        ctx.io().send(node, res);
      } catch (GridException e) {
        U.error(
            log,
            "Failed to send tx response to node (did the node leave grid?) [node="
                + node.id()
                + ", msg="
                + res
                + ']',
            e);

        if (tx != null) tx.rollback();
      }
    }
  }
Example #17
0
  /** {@inheritDoc} */
  @Override
  public GridFuture<GridCacheTxEx<K, V>> prepareAsync() {
    GridNearTxPrepareFuture<K, V> fut = prepFut.get();

    if (fut == null) {
      // Future must be created before any exception can be thrown.
      if (!prepFut.compareAndSet(null, fut = new GridNearTxPrepareFuture<K, V>(cctx, this)))
        return prepFut.get();
    } else
      // Prepare was called explicitly.
      return fut;

    if (!state(PREPARING)) {
      if (setRollbackOnly()) {
        if (timedOut())
          fut.onError(
              new GridCacheTxTimeoutException(
                  "Transaction timed out and was rolled back: " + this));
        else
          fut.onError(
              new GridException(
                  "Invalid transaction state for prepare [state="
                      + state()
                      + ", tx="
                      + this
                      + ']'));
      } else
        fut.onError(
            new GridCacheTxRollbackException(
                "Invalid transaction state for prepare [state=" + state() + ", tx=" + this + ']'));

      return fut;
    }

    // For pessimistic mode we don't distribute prepare request.
    if (pessimistic()) {
      try {
        userPrepare();

        if (!state(PREPARED)) {
          setRollbackOnly();

          fut.onError(
              new GridException(
                  "Invalid transaction state for commit [state=" + state() + ", tx=" + this + ']'));

          return fut;
        }

        fut.complete();

        return fut;
      } catch (GridException e) {
        fut.onError(e);

        return fut;
      }
    }

    try {
      cctx.topology().readLock();

      try {
        topologyVersion(cctx.topology().topologyVersion());

        userPrepare();
      } finally {
        cctx.topology().readUnlock();
      }

      // This will attempt to locally commit
      // EVENTUALLY CONSISTENT transactions.
      fut.onPreparedEC();

      // Make sure to add future before calling prepare.
      cctx.mvcc().addFuture(fut);

      fut.prepare();
    } catch (GridCacheTxTimeoutException e) {
      fut.onError(e);
    } catch (GridCacheTxOptimisticException e) {
      fut.onError(e);
    } catch (GridException e) {
      setRollbackOnly();

      String msg = "Failed to prepare transaction (will attempt rollback): " + this;

      log.error(msg, e);

      try {
        rollback();
      } catch (GridException e1) {
        U.error(log, "Failed to rollback transaction: " + this, e1);
      }

      fut.onError(new GridCacheTxRollbackException(msg, e));
    }

    return fut;
  }
  /** {@inheritDoc} */
  @Override
  public GridDeployment getDeployment(GridDeploymentMetadata meta) {
    assert meta != null;

    assert ctx.config().isPeerClassLoadingEnabled();

    // Validate metadata.
    assert meta.classLoaderId() != null;
    assert meta.senderNodeId() != null;
    assert meta.sequenceNumber() >= -1;
    assert meta.parentLoader() == null;

    if (log.isDebugEnabled())
      log.debug("Starting to peer-load class based on deployment metadata: " + meta);

    while (true) {
      List<SharedDeployment> depsToCheck = null;

      SharedDeployment dep = null;

      synchronized (mux) {
        // Check obsolete request.
        if (isDeadClassLoader(meta)) return null;

        List<SharedDeployment> deps = cache.get(meta.userVersion());

        if (deps != null) {
          assert !deps.isEmpty();

          for (SharedDeployment d : deps) {
            if (d.hasParticipant(meta.senderNodeId(), meta.classLoaderId())
                || meta.senderNodeId().equals(ctx.localNodeId())) {
              // Done.
              dep = d;

              break;
            }
          }

          if (dep == null) {
            GridTuple2<Boolean, SharedDeployment> redeployCheck = checkRedeploy(meta);

            if (!redeployCheck.get1()) {
              // Checking for redeployment encountered invalid state.
              if (log.isDebugEnabled())
                log.debug("Checking for redeployment encountered invalid state: " + meta);

              return null;
            }

            dep = redeployCheck.get2();

            if (dep == null) {
              // Find existing deployments that need to be checked
              // whether they should be reused for this request.
              for (SharedDeployment d : deps) {
                if (!d.isPendingUndeploy() && !d.isUndeployed()) {
                  if (depsToCheck == null) depsToCheck = new LinkedList<SharedDeployment>();

                  if (log.isDebugEnabled()) log.debug("Adding deployment to check: " + d);

                  depsToCheck.add(d);
                }
              }

              // If no deployment can be reused, create a new one.
              if (depsToCheck == null) {
                dep = createNewDeployment(meta, false);

                deps.add(dep);
              }
            }
          }
        } else {
          GridTuple2<Boolean, SharedDeployment> redeployCheck = checkRedeploy(meta);

          if (!redeployCheck.get1()) {
            // Checking for redeployment encountered invalid state.
            if (log.isDebugEnabled())
              log.debug("Checking for redeployment encountered invalid state: " + meta);

            return null;
          }

          dep = redeployCheck.get2();

          if (dep == null)
            // Create peer class loader.
            dep = createNewDeployment(meta, true);
        }
      }

      if (dep != null) {
        if (log.isDebugEnabled())
          log.debug("Found SHARED or CONTINUOUS deployment after first check: " + dep);

        // Cache the deployed class.
        Class<?> cls = dep.deployedClass(meta.className(), meta.alias());

        if (cls == null) {
          U.warn(
              log,
              "Failed to load peer class (ignore if class got undeployed during preloading) [alias="
                  + meta.alias()
                  + ", dep="
                  + dep
                  + ']');

          return null;
        }

        return dep;
      }

      assert meta.parentLoader() == null;
      assert depsToCheck != null;
      assert !depsToCheck.isEmpty();

      /*
       * Logic below must be performed outside of synchronization
       * because it involves network calls.
       */

      // Check if class can be loaded from existing nodes.
      // In most cases this loop will find something.
      for (SharedDeployment d : depsToCheck) {
        // Load class. Note, that remote node will not load this class.
        // The class will only be loaded on this node.
        Class<?> cls = d.deployedClass(meta.className(), meta.alias());

        if (cls != null) {
          synchronized (mux) {
            if (!d.isUndeployed() && !d.isPendingUndeploy()) {
              if (!addParticipant(d, meta)) return null;

              if (log.isDebugEnabled())
                log.debug(
                    "Acquired deployment after verifying it's availability on "
                        + "existing nodes [depCls="
                        + cls
                        + ", dep="
                        + d
                        + ", meta="
                        + meta
                        + ']');

              return d;
            }
          }
        } else if (log.isDebugEnabled()) {
          log.debug(
              "Deployment cannot be reused (class does not exist on participating nodes) [dep="
                  + d
                  + ", meta="
                  + meta
                  + ']');
        }
      }

      // We are here either because all participant nodes failed
      // or the class indeed should have a separate deployment.
      for (SharedDeployment d : depsToCheck) {
        // Temporary class loader.
        ClassLoader temp =
            new GridDeploymentClassLoader(
                GridUuid.randomUuid(),
                meta.userVersion(),
                meta.deploymentMode(),
                true,
                ctx,
                ctxLdr,
                meta.classLoaderId(),
                meta.senderNodeId(),
                meta.sequenceNumber(),
                comm,
                ctx.config().getNetworkTimeout(),
                log,
                ctx.config().getPeerClassLoadingClassPathExclude(),
                0,
                false);

        String path = U.classNameToResourceName(d.sampleClassName());

        // We check if any random class from existing deployment can be
        // loaded from sender node. If it can, then we reuse existing
        // deployment.
        InputStream rsrcIn = temp.getResourceAsStream(path);

        if (rsrcIn != null) {
          // We don't need the actual stream.
          U.closeQuiet(rsrcIn);

          synchronized (mux) {
            if (d.isUndeployed() || d.isPendingUndeploy()) continue;

            // Add new node prior to loading the class, so we attempt
            // to load the class from the latest node.
            if (!addParticipant(d, meta)) {
              if (log.isDebugEnabled())
                log.debug(
                    "Failed to add participant to deployment "
                        + "[meta="
                        + meta
                        + ", dep="
                        + dep
                        + ']');

              return null;
            }
          }

          Class<?> depCls = d.deployedClass(meta.className(), meta.alias());

          if (depCls == null) {
            U.error(
                log,
                "Failed to peer load class after loading it as a resource [alias="
                    + meta.alias()
                    + ", dep="
                    + dep
                    + ']');

            return null;
          }

          if (log.isDebugEnabled())
            log.debug(
                "Acquired deployment class after verifying other class "
                    + "availability on sender node [depCls="
                    + depCls
                    + ", rndCls="
                    + d.sampleClass()
                    + ", sampleClsName="
                    + d.sampleClassName()
                    + ", meta="
                    + meta
                    + ']');

          return d;
        } else if (log.isDebugEnabled())
          log.debug(
              "Deployment cannot be reused (random class could not be loaded from sender node) [dep="
                  + d
                  + ", meta="
                  + meta
                  + ']');
      }

      synchronized (mux) {
        if (log.isDebugEnabled())
          log.debug(
              "None of the existing class-loaders fit (will try to create a new one): " + meta);

        // Check obsolete request.
        if (isDeadClassLoader(meta)) return null;

        // Check that deployment picture has not changed.
        List<SharedDeployment> deps = cache.get(meta.userVersion());

        if (deps != null) {
          assert !deps.isEmpty();

          boolean retry = false;

          for (SharedDeployment d : deps) {
            // Double check if sender was already added.
            if (d.hasParticipant(meta.senderNodeId(), meta.classLoaderId())) {
              dep = d;

              retry = false;

              break;
            }

            // New deployment was added while outside of synchronization.
            // Need to recheck it again.
            if (!d.isPendingUndeploy() && !d.isUndeployed() && !depsToCheck.contains(d))
              retry = true;
          }

          if (retry) {
            if (log.isDebugEnabled()) log.debug("Retrying due to concurrency issues: " + meta);

            // Outer while loop.
            continue;
          }

          if (dep == null) {
            // No new deployments were added, so we can safely add ours.
            dep = createNewDeployment(meta, false);

            deps.add(dep);

            if (log.isDebugEnabled())
              log.debug(
                  "Adding new deployment within second check [dep=" + dep + ", meta=" + meta + ']');
          }
        } else {
          dep = createNewDeployment(meta, true);

          if (log.isDebugEnabled())
            log.debug(
                "Created new deployment within second check [dep=" + dep + ", meta=" + meta + ']');
        }
      }

      if (dep != null) {
        // Cache the deployed class.
        Class<?> cls = dep.deployedClass(meta.className(), meta.alias());

        if (cls == null) {
          U.warn(
              log,
              "Failed to load peer class (ignore if class got undeployed during preloading) [alias="
                  + meta.alias()
                  + ", dep="
                  + dep
                  + ']');

          return null;
        }
      }

      return dep;
    }
  }