/**
   * The Asynchronous version of setACL. The request doesn't actually until the asynchronous
   * callback is called.
   *
   * @see #setACL(String, List, int)
   */
  public void setACL(final String path, List<ACL> acl, int version, StatCallback cb, Object ctx) {
    final String clientPath = path;
    PathUtils.validatePath(clientPath);

    final String serverPath = prependChroot(clientPath);

    RequestHeader h = new RequestHeader();
    h.setType(ZooDefs.OpCode.setACL);
    SetACLRequest request = new SetACLRequest();
    request.setPath(serverPath);
    request.setAcl(acl);
    request.setVersion(version);
    SetACLResponse response = new SetACLResponse();
    cnxn.queuePacket(
        h, new ReplyHeader(), request, response, cb, clientPath, serverPath, ctx, null);
  }
  /**
   * Set the ACL for the node of the given path if such a node exists and the given version matches
   * the version of the node. Return the stat of the node.
   *
   * <p>A KeeperException with error code KeeperException.NoNode will be thrown if no node with the
   * given path exists.
   *
   * <p>A KeeperException with error code KeeperException.BadVersion will be thrown if the given
   * version does not match the node's version.
   *
   * @param path
   * @param acl
   * @param version
   * @return the stat of the node.
   * @throws InterruptedException If the server transaction is interrupted.
   * @throws KeeperException If the server signals an error with a non-zero error code.
   * @throws org.apache.zookeeper.KeeperException.InvalidACLException If the acl is invalide.
   * @throws IllegalArgumentException if an invalid path is specified
   */
  public Stat setACL(final String path, List<ACL> acl, int version)
      throws KeeperException, InterruptedException {
    final String clientPath = path;
    PathUtils.validatePath(clientPath);

    final String serverPath = prependChroot(clientPath);

    RequestHeader h = new RequestHeader();
    h.setType(ZooDefs.OpCode.setACL);
    SetACLRequest request = new SetACLRequest();
    request.setPath(serverPath);
    if (acl != null && acl.size() == 0) {
      throw new KeeperException.InvalidACLException();
    }
    request.setAcl(acl);
    request.setVersion(version);
    SetACLResponse response = new SetACLResponse();
    ReplyHeader r = cnxn.submitRequest(h, request, response, null);
    if (r.getErr() != 0) {
      throw KeeperException.create(KeeperException.Code.get(r.getErr()), clientPath);
    }
    return response.getStat();
  }
  /**
   * This method will be called inside the ProcessRequestThread, which is a singleton, so there will
   * be a single thread calling this code.
   *
   * @param request
   */
  @SuppressWarnings("unchecked")
  protected void pRequest(Request request) throws RequestProcessorException {
    // LOG.info("Prep>>> cxid = " + request.cxid + " type = " +
    // request.type + " id = 0x" + Long.toHexString(request.sessionId));
    TxnHeader txnHeader = null;
    Record txn = null;
    try {
      switch (request.type) {
        case OpCode.create:
          txnHeader =
              new TxnHeader(
                  request.sessionId, request.cxid, zks.getNextZxid(), zks.getTime(), OpCode.create);
          zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
          CreateRequest createRequest = new CreateRequest();
          ZooKeeperServer.byteBuffer2Record(request.request, createRequest);
          String path = createRequest.getPath();
          int lastSlash = path.lastIndexOf('/');
          if (lastSlash == -1 || path.indexOf('\0') != -1 || failCreate) {
            LOG.info(
                "Invalid path " + path + " with session 0x" + Long.toHexString(request.sessionId));
            throw new KeeperException.BadArgumentsException(path);
          }
          if (!fixupACL(request.authInfo, createRequest.getAcl())) {
            throw new KeeperException.InvalidACLException(path);
          }
          String parentPath = path.substring(0, lastSlash);
          ChangeRecord parentRecord = getRecordForPath(parentPath);

          checkACL(zks, parentRecord.acl, ZooDefs.Perms.CREATE, request.authInfo);
          int parentCVersion = parentRecord.stat.getCversion();
          CreateMode createMode = CreateMode.fromFlag(createRequest.getFlags());
          if (createMode.isSequential()) {
            path = path + String.format(Locale.ENGLISH, "%010d", parentCVersion);
          }
          try {
            PathUtils.validatePath(path);
          } catch (IllegalArgumentException ie) {
            LOG.info(
                "Invalid path " + path + " with session 0x" + Long.toHexString(request.sessionId));
            throw new KeeperException.BadArgumentsException(path);
          }
          try {
            if (getRecordForPath(path) != null) {
              throw new KeeperException.NodeExistsException(path);
            }
          } catch (KeeperException.NoNodeException e) {
            // ignore this one
          }
          boolean ephemeralParent = parentRecord.stat.getEphemeralOwner() != 0;
          if (ephemeralParent) {
            throw new KeeperException.NoChildrenForEphemeralsException(path);
          }
          txn =
              new CreateTxn(
                  path, createRequest.getData(), createRequest.getAcl(), createMode.isEphemeral());
          StatPersisted s = new StatPersisted();
          if (createMode.isEphemeral()) {
            s.setEphemeralOwner(request.sessionId);
          }
          parentRecord = parentRecord.duplicate(txnHeader.getZxid());
          parentRecord.childCount++;
          parentRecord.stat.setCversion(parentRecord.stat.getCversion() + 1);
          addChangeRecord(parentRecord);
          addChangeRecord(
              new ChangeRecord(txnHeader.getZxid(), path, s, 0, createRequest.getAcl()));

          break;
        case OpCode.delete:
          txnHeader =
              new TxnHeader(
                  request.sessionId, request.cxid, zks.getNextZxid(), zks.getTime(), OpCode.delete);
          zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
          DeleteRequest deleteRequest = new DeleteRequest();
          ZooKeeperServer.byteBuffer2Record(request.request, deleteRequest);
          path = deleteRequest.getPath();
          lastSlash = path.lastIndexOf('/');
          if (lastSlash == -1
              || path.indexOf('\0') != -1
              || zks.getZKDatabase().isSpecialPath(path)) {
            throw new KeeperException.BadArgumentsException(path);
          }
          parentPath = path.substring(0, lastSlash);
          parentRecord = getRecordForPath(parentPath);
          ChangeRecord nodeRecord = getRecordForPath(path);
          checkACL(zks, parentRecord.acl, ZooDefs.Perms.DELETE, request.authInfo);
          int version = deleteRequest.getVersion();
          if (version != -1 && nodeRecord.stat.getVersion() != version) {
            throw new KeeperException.BadVersionException(path);
          }
          if (nodeRecord.childCount > 0) {
            throw new KeeperException.NotEmptyException(path);
          }
          txn = new DeleteTxn(path);
          parentRecord = parentRecord.duplicate(txnHeader.getZxid());
          parentRecord.childCount--;
          parentRecord.stat.setCversion(parentRecord.stat.getCversion() + 1);
          addChangeRecord(parentRecord);
          addChangeRecord(new ChangeRecord(txnHeader.getZxid(), path, null, -1, null));
          break;
        case OpCode.setData:
          txnHeader =
              new TxnHeader(
                  request.sessionId,
                  request.cxid,
                  zks.getNextZxid(),
                  zks.getTime(),
                  OpCode.setData);
          zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
          SetDataRequest setDataRequest = new SetDataRequest();
          ZooKeeperServer.byteBuffer2Record(request.request, setDataRequest);
          path = setDataRequest.getPath();
          nodeRecord = getRecordForPath(path);
          checkACL(zks, nodeRecord.acl, ZooDefs.Perms.WRITE, request.authInfo);
          version = setDataRequest.getVersion();
          int currentVersion = nodeRecord.stat.getVersion();
          if (version != -1 && version != currentVersion) {
            throw new KeeperException.BadVersionException(path);
          }
          version = currentVersion + 1;
          txn = new SetDataTxn(path, setDataRequest.getData(), version);
          nodeRecord = nodeRecord.duplicate(txnHeader.getZxid());
          nodeRecord.stat.setVersion(version);
          addChangeRecord(nodeRecord);
          break;
        case OpCode.setACL:
          txnHeader =
              new TxnHeader(
                  request.sessionId, request.cxid, zks.getNextZxid(), zks.getTime(), OpCode.setACL);
          zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
          SetACLRequest setAclRequest = new SetACLRequest();
          ZooKeeperServer.byteBuffer2Record(request.request, setAclRequest);
          path = setAclRequest.getPath();
          if (!fixupACL(request.authInfo, setAclRequest.getAcl())) {
            throw new KeeperException.InvalidACLException(path);
          }
          nodeRecord = getRecordForPath(path);
          checkACL(zks, nodeRecord.acl, ZooDefs.Perms.ADMIN, request.authInfo);
          version = setAclRequest.getVersion();
          currentVersion = nodeRecord.stat.getAversion();
          if (version != -1 && version != currentVersion) {
            throw new KeeperException.BadVersionException(path);
          }
          version = currentVersion + 1;
          txn = new SetACLTxn(path, setAclRequest.getAcl(), version);
          nodeRecord = nodeRecord.duplicate(txnHeader.getZxid());
          nodeRecord.stat.setAversion(version);
          addChangeRecord(nodeRecord);
          break;
        case OpCode.createSession:
          txnHeader =
              new TxnHeader(
                  request.sessionId,
                  request.cxid,
                  zks.getNextZxid(),
                  zks.getTime(),
                  OpCode.createSession);
          request.request.rewind();
          int to = request.request.getInt();
          txn = new CreateSessionTxn(to);
          request.request.rewind();
          zks.sessionTracker.addSession(request.sessionId, to);
          zks.setOwner(request.sessionId, request.getOwner());
          break;
        case OpCode.closeSession:
          txnHeader =
              new TxnHeader(
                  request.sessionId,
                  request.cxid,
                  zks.getNextZxid(),
                  zks.getTime(),
                  OpCode.closeSession);
          // We don't want to do this check since the session expiration thread
          // queues up this operation without being the session owner.
          // this request is the last of the session so it should be ok
          // zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
          HashSet<String> es = zks.getZKDatabase().getEphemerals(request.sessionId);
          synchronized (zks.outstandingChanges) {
            for (ChangeRecord c : zks.outstandingChanges) {
              if (c.stat == null) {
                // Doing a delete
                es.remove(c.path);
              } else if (c.stat.getEphemeralOwner() == request.sessionId) {
                es.add(c.path);
              }
            }
            for (String path2Delete : es) {
              addChangeRecord(new ChangeRecord(txnHeader.getZxid(), path2Delete, null, 0, null));
            }

            zks.sessionTracker.setSessionClosing(request.sessionId);
          }

          LOG.info(
              "Processed session termination for sessionid: 0x"
                  + Long.toHexString(request.sessionId));
          break;
        case OpCode.sync:
        case OpCode.exists:
        case OpCode.getData:
        case OpCode.getACL:
        case OpCode.getChildren:
        case OpCode.getChildren2:
        case OpCode.ping:
        case OpCode.setWatches:
          zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
          break;
      }
    } catch (KeeperException e) {
      if (txnHeader != null) {
        txnHeader.setType(OpCode.error);
        txn = new ErrorTxn(e.code().intValue());
      }
      LOG.info(
          "Got user-level KeeperException when processing "
              + request.toString()
              + " Error Path:"
              + e.getPath()
              + " Error:"
              + e.getMessage());
      request.setException(e);
    } catch (Exception e) {
      // log at error level as we are returning a marshalling
      // error to the user
      LOG.error("Failed to process " + request, e);

      StringBuilder sb = new StringBuilder();
      ByteBuffer bb = request.request;
      if (bb != null) {
        bb.rewind();
        while (bb.hasRemaining()) {
          sb.append(Integer.toHexString(bb.get() & 0xff));
        }
      } else {
        sb.append("request buffer is null");
      }

      LOG.error("Dumping request buffer: 0x" + sb.toString());
      if (txnHeader != null) {
        txnHeader.setType(OpCode.error);
        txn = new ErrorTxn(Code.MARSHALLINGERROR.intValue());
      }
    }
    request.hdr = txnHeader;
    request.txn = txn;
    request.zxid = zks.getZxid();
    nextProcessor.processRequest(request);
  }