How to use the thrift.Thrift.TApplicationException function in thrift

TBufferedTransport.receiver(function(transin) {
    var protin = new TBinaryProtocol(transin);
    var transout = new TBufferedTransport(undefined, function(buf) {
      callback.sendReply(buf);
    });
    var protout = new TBinaryProtocol(transout);
    try {
     processor.process(protin, protout);
    } catch (err) {
      console.log(err);
      var x = new Thrift.TApplicationException(
        Thrift.TApplicationExceptionType.UNKNOWN_METHOD,
        'Unknown error'
      );
      protout.writeMessageBegin('', Thrift.MessageType.Exception, 0);
      x.write(protout);
      protout.writeMessageEnd();
      protout.flush();
    }
  })(datain);
}

AppFabricServiceClient.prototype.recv_status = function(input,mtype,rseqid) {
  var callback = this._reqs[rseqid] || function() {};
  delete this._reqs[rseqid];
  if (mtype == Thrift.MessageType.EXCEPTION) {
    var x = new Thrift.TApplicationException();
    x.read(input);
    input.readMessageEnd();
    return callback(x);
  }
  var result = new AppFabricService_status_result();
  result.read(input);
  input.readMessageEnd();

  if (null !== result.e) {
    return callback(result.e);
  }
  if (null !== result.success) {
    return callback(null, result.success);
  }
  return callback('status failed: unknown result');
};

FlowServiceClient.prototype.recv_stop = function(input,mtype,rseqid) {
  var callback = this._reqs[rseqid] || function() {};
  delete this._reqs[rseqid];
  if (mtype == Thrift.MessageType.EXCEPTION) {
    var x = new Thrift.TApplicationException();
    x.read(input);
    input.readMessageEnd();
    return callback(x);
  }
  var result = new FlowService_stop_result();
  result.read(input);
  input.readMessageEnd();

  if (null !== result.e) {
    return callback(result.e);
  }
  if (null !== result.success) {
    return callback(null, result.success);
  }
  return callback('stop failed: unknown result');
};

MetricsFrontendServiceClient.prototype.recv_getCounters = function(input,mtype,rseqid) {
  var callback = this._reqs[rseqid] || function() {};
  delete this._reqs[rseqid];
  if (mtype == Thrift.MessageType.EXCEPTION) {
    var x = new Thrift.TApplicationException();
    x.read(input);
    input.readMessageEnd();
    return callback(x);
  }
  var result = new MetricsFrontendService_getCounters_result();
  result.read(input);
  input.readMessageEnd();

  if (null !== result.e) {
    return callback(result.e);
  }
  if (null !== result.success) {
    return callback(null, result.success);
  }
  return callback('getCounters failed: unknown result');
};

MetadataServiceClient.prototype.recv_createDataset = function(input,mtype,rseqid) {
  var callback = this._reqs[rseqid] || function() {};
  delete this._reqs[rseqid];
  if (mtype == Thrift.MessageType.EXCEPTION) {
    var x = new Thrift.TApplicationException();
    x.read(input);
    input.readMessageEnd();
    return callback(x);
  }
  var result = new MetadataService_createDataset_result();
  result.read(input);
  input.readMessageEnd();

  if (null !== result.e) {
    return callback(result.e);
  }
  if (null !== result.success) {
    return callback(null, result.success);
  }
  return callback('createDataset failed: unknown result');
};