@Override
 public void recover(IntStream stream, RecognitionException ex) {
   if (recoveryListener != null) recoveryListener.beginErrorRecovery();
   removeUnexpectedElements();
   if (ex instanceof FailedPredicateException && ex.token.getType() == Token.EOF) {
     failedPredicateAtEOF = true;
   }
   super.recover(stream, ex);
   if (recoveryListener != null) recoveryListener.endErrorRecovery();
 }
  /** Recovers the state of the shard from the gateway. */
  public void recover(final boolean indexShouldExists, final RecoveryListener listener)
      throws IndexShardGatewayRecoveryException, IgnoreGatewayRecoveryException {
    if (indexShard.state() == IndexShardState.CLOSED) {
      // got closed on us, just ignore this recovery
      listener.onIgnoreRecovery("shard closed");
      return;
    }
    if (!indexShard.routingEntry().primary()) {
      listener.onRecoveryFailed(
          new IndexShardGatewayRecoveryException(
              shardId, "Trying to recover when the shard is in backup state", null));
      return;
    }
    try {
      if (indexShard.routingEntry().restoreSource() != null) {
        indexShard.recovering("from snapshot");
      } else {
        indexShard.recovering("from gateway");
      }
    } catch (IllegalIndexShardStateException e) {
      // that's fine, since we might be called concurrently, just ignore this, we are already
      // recovering
      listener.onIgnoreRecovery("already in recovering process, " + e.getMessage());
      return;
    }

    threadPool
        .generic()
        .execute(
            new Runnable() {
              @Override
              public void run() {
                recoveryStatus = new RecoveryStatus();
                recoveryStatus.updateStage(RecoveryStatus.Stage.INIT);

                try {
                  if (indexShard.routingEntry().restoreSource() != null) {
                    logger.debug(
                        "restoring from {} ...", indexShard.routingEntry().restoreSource());
                    snapshotService.restore(recoveryStatus);
                  } else {
                    logger.debug("starting recovery from {} ...", shardGateway);
                    shardGateway.recover(indexShouldExists, recoveryStatus);
                  }

                  lastIndexVersion = recoveryStatus.index().version();
                  lastTranslogId = -1;
                  lastTranslogLength = 0;
                  lastTotalTranslogOperations =
                      recoveryStatus.translog().currentTranslogOperations();

                  // start the shard if the gateway has not started it already. Note that if the
                  // gateway
                  // moved shard to POST_RECOVERY, it may have been started as well if:
                  // 1) master sent a new cluster state indicating shard is initializing
                  // 2) IndicesClusterStateService#applyInitializingShard will send a shard started
                  // event
                  // 3) Master will mark shard as started and this will be processed locally.
                  IndexShardState shardState = indexShard.state();
                  if (shardState != IndexShardState.POST_RECOVERY
                      && shardState != IndexShardState.STARTED) {
                    indexShard.postRecovery("post recovery from gateway");
                  }
                  // refresh the shard
                  indexShard.refresh(new Engine.Refresh("post_gateway").force(true));

                  recoveryStatus.time(System.currentTimeMillis() - recoveryStatus.startTime());
                  recoveryStatus.updateStage(RecoveryStatus.Stage.DONE);

                  if (logger.isDebugEnabled()) {
                    logger.debug(
                        "recovery completed from [{}], took [{}]",
                        shardGateway,
                        timeValueMillis(recoveryStatus.time()));
                  } else if (logger.isTraceEnabled()) {
                    StringBuilder sb = new StringBuilder();
                    sb.append("recovery completed from ")
                        .append(shardGateway)
                        .append(", took [")
                        .append(timeValueMillis(recoveryStatus.time()))
                        .append("]\n");
                    sb.append("    index    : files           [")
                        .append(recoveryStatus.index().numberOfFiles())
                        .append("] with total_size [")
                        .append(new ByteSizeValue(recoveryStatus.index().totalSize()))
                        .append("], took[")
                        .append(TimeValue.timeValueMillis(recoveryStatus.index().time()))
                        .append("]\n");
                    sb.append("             : recovered_files [")
                        .append(recoveryStatus.index().numberOfRecoveredFiles())
                        .append("] with total_size [")
                        .append(new ByteSizeValue(recoveryStatus.index().recoveredTotalSize()))
                        .append("]\n");
                    sb.append("             : reusing_files   [")
                        .append(recoveryStatus.index().numberOfReusedFiles())
                        .append("] with total_size [")
                        .append(new ByteSizeValue(recoveryStatus.index().reusedTotalSize()))
                        .append("]\n");
                    sb.append("    start    : took [")
                        .append(TimeValue.timeValueMillis(recoveryStatus.start().time()))
                        .append("], check_index [")
                        .append(timeValueMillis(recoveryStatus.start().checkIndexTime()))
                        .append("]\n");
                    sb.append("    translog : number_of_operations [")
                        .append(recoveryStatus.translog().currentTranslogOperations())
                        .append("], took [")
                        .append(TimeValue.timeValueMillis(recoveryStatus.translog().time()))
                        .append("]");
                    logger.trace(sb.toString());
                  }
                  listener.onRecoveryDone();
                  scheduleSnapshotIfNeeded();
                } catch (IndexShardGatewayRecoveryException e) {
                  if (indexShard.state() == IndexShardState.CLOSED) {
                    // got closed on us, just ignore this recovery
                    listener.onIgnoreRecovery("shard closed");
                    return;
                  }
                  if ((e.getCause() instanceof IndexShardClosedException)
                      || (e.getCause() instanceof IndexShardNotStartedException)) {
                    // got closed on us, just ignore this recovery
                    listener.onIgnoreRecovery("shard closed");
                    return;
                  }
                  listener.onRecoveryFailed(e);
                } catch (IndexShardClosedException e) {
                  listener.onIgnoreRecovery("shard closed");
                } catch (IndexShardNotStartedException e) {
                  listener.onIgnoreRecovery("shard closed");
                } catch (Exception e) {
                  if (indexShard.state() == IndexShardState.CLOSED) {
                    // got closed on us, just ignore this recovery
                    listener.onIgnoreRecovery("shard closed");
                    return;
                  }
                  listener.onRecoveryFailed(
                      new IndexShardGatewayRecoveryException(shardId, "failed recovery", e));
                }
              }
            });
  }